I don't think that the simple fact of not being able to update with KB will make pirates want to switch to OS X. In fact, they're pirates because they don't pay for the software, but they steal it. Last time I checked, Apple made you pay for the updates as well as the original Operating System.
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There might be a problem there. If you use the GPL'd code you write at home, you will have to release your code at work under the GPL as well.
I don't think that the simple fact of not being able to update with KB will make pirates want to switch to OS X. In fact, they're pirates because they don't pay for the software, but they steal it. Last time I checked, Apple made you pay for the updates as well as the original Operating System.
This is the same diversity that is holding desktop linux back, however.