Thanks for your thoughtful and polite reply. Since there seem to be some actual reasonable people reading these posts, I'll be glad to follow up.
As a computer science professor, I'm fairly well aware of issues of security and privacy. Both approaches that I proposed actually do a good job of protecting reader security; I'm not sure if anyone read my posts very carefully.
1. If Amazon supplied us with order numbers, we could use those to identify a single sale, but not who made that sale. I could use that to populate a database for a single registration code to the extra materials. That code would have an expiration date. Unless Amazon uses a very dumb process for generating order numbers, there should not be any way to reverse-engineer user information from the order numbers.
2. Optionally, Amazon could supply us with a mechanism to send a single email to a reader through an anonymous process which would contain a registration number.
Although all processes have some possibility of a security breech, I don't see how either of the above approaches opens up anyone to more insecurity.
By giving in to the "people will steal your intellectual property no matter what you do" mentality, soon there will not be anyone who can afford to spend the time to produce new material. This is the original purpose of the copyright laws.
Now, as to Amazon having a good reason to do this, I understand the concept, but better customer service should generate better sales -- isn't that their whole raison d'etre?