Maybe it's not a true quantum "computer", but is that bad? The first electronic "problem solving machines" weren't true computers, either. That doesn't mean that this "custom" quantum machine isn't a useful step in the right direction...
The problem is the direction it is a step in may be a dead end. I don't entirely understand why, but it seems that the technology they are using is fundamentally limited in certain ways, such that there are entire classes of useful quantum algorithms (most notably Shor's algorithm for calculating prime factors) that cannot be implemented on it.
Yeah, I noticed that. He has four input pipes and four output pipes, but two of the outputs only depend on two inputs, so it can't work right, as in a correct adder, only the least significant bit has only two dependencies.
Even if we join two of his output pipes to make an or to give the third bit, it doesn't look like any of those results are going to be right other than the least significant bit.
If, however, he swapped the two pipes coming out of the lower left-hand side half adder, he'd get:
As a side issue, I kind of think that the specific photos Paulo has there are a tad mis-wired; it supposed to a full 2-bit adder, but doesn't quite work right if all 3 inputs are on (last time I looked at this was 2004, maybe someone can correct or confirm that).
Yeah, I noticed that. He has four input pipes and four output pipes, but two of the outputs only depend on two inputs, so it can't work right, as in a correct adder, only the least significant bit has only two dependencies.
A few decades ago there was some academic playing around with base-3 computers, which used 'Trinary Digits' or Trits.
Should be called 'ternary digits'... unary, binary, ternary, quaternary, etc. However, they may have been influenced in the nomenclature by the fact that the only convenient abbreviation of "ternary digits" is "tits".
If you mail something to somebody, even by mistake, they have no obligation to return it or to send you money after the fact. Any payment must have been arranged beforehand. There are laws on the books specifically addressing this, which are meant to prevent unscrupulous companies from sending items to people out of the blue and then demanding payment for them.
I don't believe these laws apply in this situation, because the items were requested. The question is whether a contract of sale exists; if it does, people can keep them. If it doesn't, Amazon may be able to get its property returned. They certainly *can't* demand the additional payment, under any circumstances.
Why not? You gave them your CC and agreed to pay for 50%. How are you not liable for the charge?
1. See price 2. Agree to it 3. Place order 4. Mistakenly not get billed 5. Get billed in the end anyways
How does #4 negate #2?
You seem to have a misunderstanding of what happened here, which is more like:
1. See description of offer. 2. Choose to add offer to list of items you wish to purchase 3. See incorrect price on list and at bottom of list of items 4. Agree to pay the incorrect price by your credit card 5. Get billed the amount you agreed to pay 6. Get billed the remainder later.
The page on which these people agreed to make a payment clearly stated the amount they would be charged, and that amount was the mistaken amount. These customers did nothing which would legally indicate they accepted to pay the full price.
This would be true only if a contract exists. Since a price of $0 nets Amazon no consideration for the contract - there is no contract - you meerly had a user request delivery of an item under color of contract, which was still open to interpretation until the contract was in fact formed (once amazon actually got something for the trade).
I assume the total price wasn't actually $0: there would have been an additional charge for delivery. This is probably enough consideration to form a contract.
This is also an excellent example of unjust enrichment - Amazon is a store - stores usually sell product - therefore it should have been obvious that preposed price of 0 was not valid - and Amazon would be justified in going to court in search of a judgement for the value of the product delivered.
Should have been obvious? Hard to tell. I've run a web store in the past that has intentionally put items out with a zero price tag, in the hope that we'd make enough money on repeat orders to cover the cost (we did). Some vendors put a large proportion of the cost of an item into the delivery charge -- see Amazon's "buy it used" for an example: most used books on Amazon UK sell for ~£0.25 (+ £2.75 delivery). It's hard to tell whether this kind of thing is a mistake or intentional.
This in particular is a clear case of Unjust Enrichment.
Perhaps. But:
* The only equitable remedy is to allow Amazon to claim back their DVDs, not to force the consumers to pay for them, as it is not clear that the consumers would have entered into a contract at the full price. Amazon are refusing to accept returns of opened DVDs. However, according to the article you linked, it is debatable whether this outcome is a valid outcome of an enrichment case. * If a financial award to Amazon were to be made, the value of the DVDs to the recipients would have to be judged. Based on the fact that we do not know whether they would have purchased them at full retail price or not, this could be anywhere between full retail and zero. * Unjust Enrichment cases involve the position of the recipient of the enrichment. Look at the article you linked to; there are 5 different defences available, according to it. Of these, any of Amazon's customers may be able to claim change of position (e.g., they do not have cash to pay for the DVD and have damaged it such that it cannot be returned) or agency (e.g. the DVD was purchased as a gift).
Under English common law you're not bound by a contract if you make a mistake on price (or something else) and the other party suspects you're making a mistake and takes advantage of it. Here, I think most people would have realised this was a mistake by Amazon's systems.
Yes, although it's far from guaranteed that they all did.
Besides, even in this case, Amazon could as you suggest rely on cases like Hartog v. Colin & Shields and have the contract rescinded.
With the contract rescinded, they are now unable to demand payment. All they can do is petition the court for an order that their goods be returned.
Yes, I would consider it stealing if you try to take advantage of a price mistake (especially if you do it to make money off ebay)
As would I. I have little sympathy for the people who jumped on this mistake and tried to milk it. But there are people involved here who did not do this, as well. People who just tried to buy stuff, perhaps didn't notice that they had been charged less than they should have been, and then went on to spend the money they would have spent on the DVDs on other stuff. DVDs are luxury items, many of us have quite limited budgets to spend on such things.
AND you complain when the merchant wants to correct it.
The merchant is perfectly entitle to correct it, IMO. Here's how they should go about doing this:
Write to the customer, apologising for the problem, and asking them to either (a) pay for the item or (b) fill in a simple form so that Amazon can arrange a convenient time for them to send somebody around to collect the unwanted item, at Amazon's own expense, and with a minimum of inconvenience to the customer.
When, inevitably, large numbers of people do neither of these things, send them an invoice.
When, inevitably, large numbers of people do not pay the invoice, send a notice of recovery of debt in a court of law.
When, inevitably, large numbers of people ignore this letter, take one of them to court, and ask a court whether it believes the money can legally be recovered. If it can, then take the rest to court.
How this is different from what Amazon are doing:
People who have honestly made a mistake, and cannot afford the items they have purchased, should be allowed to return them. The mistake is Amazon's, so it should not inconvenience these people. Amazon are not allowing returns of opened packages, and are not making it as easy as possible for people to return the packages. They should be doing both of these things.
Unexpectedly putting a charge on somebody's credit card could cause them all kinds of hassle, additional charges for going over credit limits, etc. They may not have received the correspondence from Amazon for a variety of reasons, or may just have discarded it as junk mail. These people shouldn't be penalised for Amazon's mistake.
The legal situation is far from clear. As I see it, it may well be that Amazon cannot legally recover this money. For them to use some dubious method to do so anyway would be extremely bad.
Now, IANAL, but I have read many times on slashdot about cases such as the one with the animal (I forgot, was it cow or horse or sth?) that was cheap for meat but was not sterile after all so the court annuled the low price contract.
Soon after, the plaintiff tendered to Hiram Walker, one of the defendants, $80, and demanded the cow. Walker refused to take the money or deliver the cow.
The vendor decided to cancel the contract before taking payment, not afterwards. This makes a substantial difference.
I think the problem with Amazon's deal isn't really any different than walking into a store, taking something to the cashier, having the cashier just put it in a bag and leaving without paying. Even if the cashier says "just go ahead and take it", that doesn't make it right.
Doesn't it? I did pretty much this based on a combination of a reduction offer and a discount offer that my local supermarket offered last year: in fact, they paid me to take away their goods. Are you saying it was wrong of me to do so, despite the fact that the staff at the store thought this was a perfectly reasonable thing to do?
Another scenario: you order the DVD box sets from Amazon but a few weeks later (after the return window), you realize that you got charged too much for the purchase. Amazon refuses to refund the overcharge. Is Amazon right or wrong? After all, at the end of the transaction, you agreed to a price for the delivered goods.
If the price I paid is the price that was displayed on the site, then Amazon's right. If the price I paid is higher than what was displayed on the site when I confirmed that I wanted to buy the goods, then clearly Amazon must refund the difference. Otherwise, there isn't any clarity.
Although, where I live, consumer protection law would require Amazon to refund me anyway, as long as I notified them within 7 days and returned the goods unopened.
At least in german law at least there is the possibility that the contract is void because Amazon did not intend to enter the contract under the stated terms. In this case you must return the goods, but Amazon is liable for any damages that they caused you due to their mistake. I would expect these to be much larger than the price of a DVD. (Shipping cost, legal costs, etc.)
This may be true in the UK. AFAIK, it has yet to be tested here whether a contract formed by a computer under error is valid or not. But there is a heavy bias towards consumers.
And even if it was deemed invalid, the terms the consumer would get would be a lot better than Amazons: they couldn't be forced to pay, even if they had opened the DVDs, Amazon would just have to take them back. Amazon would also have to arrange shipping, probably with collection, at a date & time that is convenient for the consumer.
That said, even if it isn't a contract in the traditional sense, promissory estoppel may prevent Amazon from claiming any money: they promised to supply the goods without charge.
This is a much weaker claim than a contract, though.
A contract of sale can still be established even is the agreed price is zero (and it was agreed, because it's what the website presented to the customer and was what the card was charged).
In neither country is this true: both require consideration for a contract. If the payment is nothing, what do Amazon gain from the contract? If they gain nothing, it isn't a contract.
It is for this reason that fraud protection exists.
You're right, except you're forgetting that fraud protection laws also protect the merchant.
Not in this case, they don't. There is no legal way Amazon can charge these consumers: they quoted a price (whether mistakenly or intentionally, it doesn't matter, the price was quoted on their web site where anybody could see it), took payment, and delivered the goods. A contract was formed, and now Amazon are expecting the customers to honour a different one.
Tell me, what exact law did any of those customers break? Because the law Amazon are breaking is quite clear: by instructing their card acquirer to take additional payments from their customers, they are declaring that they have been authorized by the customer to do so, which is clearly untrue. They are therefore obtaining money by deception.
If the customer is legally in the wrong, then Amazon are free to pursue compensation in court. Trying to obtain it directly by themselves, however, is not a legally justifiable action.
It is quite common that companies send goods to people (mostly registered customers) that they have not ordered, and supply an invoice. People either have to just pay, or to call the company, complain and return the goods.
Or not pay. And when the company tries to collect the "debt" point out that no contract exists for the sale, so they can go spin. But they can have their goods back if they come to collect them at a reasonable time.
In the US, that last sentence doesn't apply, because of a rather interesting federal law concerning this practice: you'd get to keep the goods without paying for them there. But even in other countries, it is not the consumer's responsibility to return and/or pay for goods they did not order.
Of course, none of this applies to the current situation, where the customer requested the goods were supplied, were quoted a price ($0 + $x delivery), and then paid that price, only to be told later that the price had been changed. By my understanding, this means a contract has been formed, and Amazon are just plain out of luck. Legally speaking.
Not that I think they really did, but is it even legal for them to pull this bait and switch?
No. You can't ask somebody to pay one price for something and then charge them something else, even if you've previously told them the terms will be what you later change them back to be. This is called the "last shot" rule: the last exchange between vendor and purchaser determines what's in a contract: if it contradicts anything agreed previously, then the previous agreement is cancelled.
They can't charge your card without your authorization, right? RIGHT?!
Right. So you talk to your bank and ask them to charge it back. The bank will ask a few question and do so, the money appearing back in your account after ~7 days in my experience. At the other end, Amazon will receive a number of charges from their bank for the privelege of dealing with the mess. Serves 'em right.
I don't know about US law, but in the UK once the goods have been paid for and received, the contract of sale has been established and they couldn't do anything about it.
US law is pretty identical to UK in this respect. But the point here is that the customers *haven't* been charged for the goods, so it could be argued that there is no contract.
But then, presumably, all of them paid for delivery and/or other items in the order, which could be considered to have formed a contract.
What's certainly true, however, is that Amazon have no authorization to take those payments from those credit cards. Extracting an unauthorized payment is credit card fraud. I hope all of those customers take the case straight to their card issuers and ask them to refund the unauthorized payments, because that's going to cause Amazon a whole load of shit.
As an interesting side point, the supermarket near me will effectively pay you to take home food from the reductions counter when their tills apply a promotional discount greater than the price the food has been reduced to! I don't think they'd have a leg to stand on if they demanded it back after the sale had completed.
If that's a Tesco, they had a software update on their checkouts late last year that prevents this from happening any more. Discounts are no longer applied on top of reductions.
Your player will not be disabled. It will work just as well as it always has. It's just that no new discs will be made that can play on it.
I could trivially argue in a court of law that the purpose of a media player is not only to play already existing media, but future media that is advertised using the same media type name (e.g. an HD-DVD player should be capable of playing all HD-DVD media), and that any action taken by somebody to prevent that happening in effect causes damage to the player which devalues it to the point of almost worthlessness.
Since the keys are individual, the only reason, apart from a mistake, that this would happen is because you've released the keys from your player. In the case of a mistake, I'm sure you could argue yourself into getting a new player.
And, as there's no law against releasing them intentionally, presumably you could do so in this case, too.
Slashdot Mirror
Maybe it's not a true quantum "computer", but is that bad? The first electronic "problem solving machines" weren't true computers, either. That doesn't mean that this "custom" quantum machine isn't a useful step in the right direction...
The problem is the direction it is a step in may be a dead end. I don't entirely understand why, but it seems that the technology they are using is fundamentally limited in certain ways, such that there are entire classes of useful quantum algorithms (most notably Shor's algorithm for calculating prime factors) that cannot be implemented on it.
I gave up on evolution when I found a bug before I'd even managed to configure it to read my mail.
I'll tell you who are Interface Nazis. The developers for software that ends with an 'imp' and starts with a 'G'.
And GNOME was developed on the UI toolkit originally developed for which famous piece of software?
It's called fluidics, and it's decades old.
It uses compressed air or water to create logic circuits.
There was a big interest during the cold war, since they wouldn't be affected by the electromagnetic pulse of a nuclear bomb.
To be fair, the gates this guy has built appear to be substantially simpler (and therefore probably more useful) than the old-style ones.
In more detail, I'm looking at this picture: http://alumni.media.mit.edu/~paulo/courses/howmak
From his description of the gates, and naming the inputs a1, b1, a2, b2 from top to bottom, the outputs (also from top to bottom) are:
o1 = a1 ^ b1
o2 = (a1 & b1) ^ (a2 & b2)
o3 = a1 & b1 & a2 & b2
o4 = a2 ^ b2
The correct outputs for an adder should be: o1 = a1 ^ b1
o2 = a2 ^ b2 ^ (a1&b1)
o3 = a2&b2 | (a1&b1&(a2^b2))
Even if we join two of his output pipes to make an or to give the third bit, it doesn't look like any of those results are going to be right other than the least significant bit.
If, however, he swapped the two pipes coming out of the lower left-hand side half adder, he'd get:
o1 = a1 ^ b1
o2 = (a1 & b1) ^ (a2 ^ b2)
o3 = a1 & b1 & (a2 ^ b2)
o4 = a2 & b2
So if he connected o3 and o4 together, he'd have the correct result.
As a side issue, I kind of think that the specific photos Paulo has there are a tad mis-wired; it supposed to a full 2-bit adder, but doesn't quite work right if all 3 inputs are on (last time I looked at this was 2004, maybe someone can correct or confirm that).
Yeah, I noticed that. He has four input pipes and four output pipes, but two of the outputs only depend on two inputs, so it can't work right, as in a correct adder, only the least significant bit has only two dependencies.
go forth and build an array to save my creations. Make it 100 qubits long, 30 qubits wide, and 10 qubits deep
CREATE AR 100 30 10 * * QUBITS ALLOT
?
The metric system is the tool of the devil! My car gets forty rods to the hogshead, and that's the way I likes it!
Jesus, you should start looking for a fuel leak.
A few decades ago there was some academic playing around with base-3 computers, which used 'Trinary Digits' or Trits.
Should be called 'ternary digits'... unary, binary, ternary, quaternary, etc. However, they may have been influenced in the nomenclature by the fact that the only convenient abbreviation of "ternary digits" is "tits".
If you mail something to somebody, even by mistake, they have no obligation to return it or to send you money after the fact. Any payment must have been arranged beforehand. There are laws on the books specifically addressing this, which are meant to prevent unscrupulous companies from sending items to people out of the blue and then demanding payment for them.
I don't believe these laws apply in this situation, because the items were requested. The question is whether a contract of sale exists; if it does, people can keep them. If it doesn't, Amazon may be able to get its property returned. They certainly *can't* demand the additional payment, under any circumstances.
Why not? You gave them your CC and agreed to pay for 50%. How are you not liable for the charge?
1. See price
2. Agree to it
3. Place order
4. Mistakenly not get billed
5. Get billed in the end anyways
How does #4 negate #2?
You seem to have a misunderstanding of what happened here, which is more like:
1. See description of offer.
2. Choose to add offer to list of items you wish to purchase
3. See incorrect price on list and at bottom of list of items
4. Agree to pay the incorrect price by your credit card
5. Get billed the amount you agreed to pay
6. Get billed the remainder later.
The page on which these people agreed to make a payment clearly stated the amount they would be charged, and that amount was the mistaken amount. These customers did nothing which would legally indicate they accepted to pay the full price.
This would be true only if a contract exists. Since a price of $0 nets Amazon no consideration for the contract - there is no contract - you meerly had a user request delivery of an item under color of contract, which was still open to interpretation until the contract was in fact formed (once amazon actually got something for the trade).
I assume the total price wasn't actually $0: there would have been an additional charge for delivery. This is probably enough consideration to form a contract.
This is also an excellent example of unjust enrichment - Amazon is a store - stores usually sell product - therefore it should have been obvious that preposed price of 0 was not valid - and Amazon would be justified in going to court in search of a judgement for the value of the product delivered.
Should have been obvious? Hard to tell. I've run a web store in the past that has intentionally put items out with a zero price tag, in the hope that we'd make enough money on repeat orders to cover the cost (we did). Some vendors put a large proportion of the cost of an item into the delivery charge -- see Amazon's "buy it used" for an example: most used books on Amazon UK sell for ~£0.25 (+ £2.75 delivery). It's hard to tell whether this kind of thing is a mistake or intentional.
This in particular is a clear case of Unjust Enrichment.
Perhaps. But:
* The only equitable remedy is to allow Amazon to claim back their DVDs, not to force the consumers to pay for them, as it is not clear that the consumers would have entered into a contract at the full price. Amazon are refusing to accept returns of opened DVDs. However, according to the article you linked, it is debatable whether this outcome is a valid outcome of an enrichment case.
* If a financial award to Amazon were to be made, the value of the DVDs to the recipients would have to be judged. Based on the fact that we do not know whether they would have purchased them at full retail price or not, this could be anywhere between full retail and zero.
* Unjust Enrichment cases involve the position of the recipient of the enrichment. Look at the article you linked to; there are 5 different defences available, according to it. Of these, any of Amazon's customers may be able to claim change of position (e.g., they do not have cash to pay for the DVD and have damaged it such that it cannot be returned) or agency (e.g. the DVD was purchased as a gift).
The result of such a case is far from clear.
Under English common law you're not bound by a contract if you make a mistake on price (or something else) and the other party suspects you're making a mistake and takes advantage of it. Here, I think most people would have realised this was a mistake by Amazon's systems.
Yes, although it's far from guaranteed that they all did.
Besides, even in this case, Amazon could as you suggest rely on cases like Hartog v. Colin & Shields and have the contract rescinded.
With the contract rescinded, they are now unable to demand payment. All they can do is petition the court for an order that their goods be returned.
As would I. I have little sympathy for the people who jumped on this mistake and tried to milk it. But there are people involved here who did not do this, as well. People who just tried to buy stuff, perhaps didn't notice that they had been charged less than they should have been, and then went on to spend the money they would have spent on the DVDs on other stuff. DVDs are luxury items, many of us have quite limited budgets to spend on such things.
AND you complain when the merchant wants to correct it.
The merchant is perfectly entitle to correct it, IMO. Here's how they should go about doing this:
How this is different from what Amazon are doing:
Now, IANAL, but I have read many times on slashdot about cases such as the one with the animal (I forgot, was it cow or horse or sth?) that was cheap for meat but was not sterile after all so the court annuled the low price contract.
You're probably talking about Sherwood v Walker. Note this text:
The vendor decided to cancel the contract before taking payment, not afterwards. This makes a substantial difference.
I think the problem with Amazon's deal isn't really any different than walking into a store, taking something to the cashier, having the cashier just put it in a bag and leaving without paying. Even if the cashier says "just go ahead and take it", that doesn't make it right.
Doesn't it? I did pretty much this based on a combination of a reduction offer and a discount offer that my local supermarket offered last year: in fact, they paid me to take away their goods. Are you saying it was wrong of me to do so, despite the fact that the staff at the store thought this was a perfectly reasonable thing to do?
Another scenario: you order the DVD box sets from Amazon but a few weeks later (after the return window), you realize that you got charged too much for the purchase. Amazon refuses to refund the overcharge. Is Amazon right or wrong? After all, at the end of the transaction, you agreed to a price for the delivered goods.
If the price I paid is the price that was displayed on the site, then Amazon's right. If the price I paid is higher than what was displayed on the site when I confirmed that I wanted to buy the goods, then clearly Amazon must refund the difference. Otherwise, there isn't any clarity.
Although, where I live, consumer protection law would require Amazon to refund me anyway, as long as I notified them within 7 days and returned the goods unopened.
At least in german law at least there is the possibility that the contract is void because Amazon did not intend to enter the contract under the stated terms. In this case you must return the goods, but Amazon is liable for any damages that they caused you due to their mistake. I would expect these to be much larger than the price of a DVD. (Shipping cost, legal costs, etc.)
This may be true in the UK. AFAIK, it has yet to be tested here whether a contract formed by a computer under error is valid or not. But there is a heavy bias towards consumers.
And even if it was deemed invalid, the terms the consumer would get would be a lot better than Amazons: they couldn't be forced to pay, even if they had opened the DVDs, Amazon would just have to take them back. Amazon would also have to arrange shipping, probably with collection, at a date & time that is convenient for the consumer.
I wrote:
"If they gain nothing, it isn't a contract."
That said, even if it isn't a contract in the traditional sense, promissory estoppel may prevent Amazon from claiming any money: they promised to supply the goods without charge.
This is a much weaker claim than a contract, though.
A contract of sale can still be established even is the agreed price is zero (and it was agreed, because it's what the website presented to the customer and was what the card was charged).
In neither country is this true: both require consideration for a contract. If the payment is nothing, what do Amazon gain from the contract? If they gain nothing, it isn't a contract.
It is for this reason that fraud protection exists.
You're right, except you're forgetting that fraud protection laws also protect the merchant.
Not in this case, they don't. There is no legal way Amazon can charge these consumers: they quoted a price (whether mistakenly or intentionally, it doesn't matter, the price was quoted on their web site where anybody could see it), took payment, and delivered the goods. A contract was formed, and now Amazon are expecting the customers to honour a different one.
Tell me, what exact law did any of those customers break? Because the law Amazon are breaking is quite clear: by instructing their card acquirer to take additional payments from their customers, they are declaring that they have been authorized by the customer to do so, which is clearly untrue. They are therefore obtaining money by deception.
If the customer is legally in the wrong, then Amazon are free to pursue compensation in court. Trying to obtain it directly by themselves, however, is not a legally justifiable action.
It is quite common that companies send goods to people (mostly registered customers) that they have not ordered, and supply an invoice. People either have to just pay, or to call the company, complain and return the goods.
Or not pay. And when the company tries to collect the "debt" point out that no contract exists for the sale, so they can go spin. But they can have their goods back if they come to collect them at a reasonable time.
In the US, that last sentence doesn't apply, because of a rather interesting federal law concerning this practice: you'd get to keep the goods without paying for them there. But even in other countries, it is not the consumer's responsibility to return and/or pay for goods they did not order.
Of course, none of this applies to the current situation, where the customer requested the goods were supplied, were quoted a price ($0 + $x delivery), and then paid that price, only to be told later that the price had been changed. By my understanding, this means a contract has been formed, and Amazon are just plain out of luck. Legally speaking.
Not that I think they really did, but is it even legal for them to pull this bait and switch?
No. You can't ask somebody to pay one price for something and then charge them something else, even if you've previously told them the terms will be what you later change them back to be. This is called the "last shot" rule: the last exchange between vendor and purchaser determines what's in a contract: if it contradicts anything agreed previously, then the previous agreement is cancelled.
They can't charge your card without your authorization, right? RIGHT?!
Right. So you talk to your bank and ask them to charge it back. The bank will ask a few question and do so, the money appearing back in your account after ~7 days in my experience. At the other end, Amazon will receive a number of charges from their bank for the privelege of dealing with the mess. Serves 'em right.
I don't know about US law, but in the UK once the goods have been paid for and received, the contract of sale has been established and they couldn't do anything about it.
US law is pretty identical to UK in this respect. But the point here is that the customers *haven't* been charged for the goods, so it could be argued that there is no contract.
But then, presumably, all of them paid for delivery and/or other items in the order, which could be considered to have formed a contract.
What's certainly true, however, is that Amazon have no authorization to take those payments from those credit cards. Extracting an unauthorized payment is credit card fraud. I hope all of those customers take the case straight to their card issuers and ask them to refund the unauthorized payments, because that's going to cause Amazon a whole load of shit.
As an interesting side point, the supermarket near me will effectively pay you to take home food from the reductions counter when their tills apply a promotional discount greater than the price the food has been reduced to! I don't think they'd have a leg to stand on if they demanded it back after the sale had completed.
If that's a Tesco, they had a software update on their checkouts late last year that prevents this from happening any more. Discounts are no longer applied on top of reductions.
Your player will not be disabled. It will work just as well as it always has. It's just that no new discs will be made that can play on it.
I could trivially argue in a court of law that the purpose of a media player is not only to play already existing media, but future media that is advertised using the same media type name (e.g. an HD-DVD player should be capable of playing all HD-DVD media), and that any action taken by somebody to prevent that happening in effect causes damage to the player which devalues it to the point of almost worthlessness.
Since the keys are individual, the only reason, apart from a mistake, that this would happen is because you've released the keys from your player. In the case of a mistake, I'm sure you could argue yourself into getting a new player.
And, as there's no law against releasing them intentionally, presumably you could do so in this case, too.