Providing Linux Distributions And Source Code?

Jens asks: "In my neighborhood I am the only one with a leased line and so I started burning Linux distributions, mostly current snapshots of the Debian GNU/Linux binary-i386 tree, on CD. I sell them for a small fee, and I sell about one to two CD sets a week. Now I realize that the GNU Public Licence permits this as long as I can guarantee that for at least three years after selling a CD I can provide a source distribution of the packages that were included on the CDs. As downloading costs money and time, mirroring an extra 3-4GB per needed snapshot is no option for me since I don't make any real money selling those snapshots. This is all very small-volume work and I do it for the fun of it and to provide people without Internet access with current Linux systems. But I'm wondering if there are other ways..." Read on...

"Some other points:

• Can I gamble on the fact that IF in three years time someone asks me for the source distro, I can just download a current source snapshot and send that one?
• Can I ask the customer that we agree on ignoring that respect of the GPL (which would be bad for ethics, but an option)? [I would expect (and sincerely hope) not, but it doesn't hurt to ask.]
• And finally, what would I have to expect if in two years time, someone would want the source from me and I couldn't provide it (for whatever reason)?

I did read the GPL, however I'm not that good at parsing legalese so please don't tell me to RTFLicence right away. Any help would be appreciated."