The Liberty Trilogy deals with the termination of government. Until a substantial number of people graduate from a freedom school and quit their government jobs, it's unlikely that anyone will notice or care - but when they do notice, they will care; and a witch-hunt will begin. Transition to Liberty imagines what forms it may take.
Why does privacy matter?
One possibility is that snoops will try to identify all who are taking part in the great walk-out, whether currently in government employ or not. So they would just love to have a list of those who bought these books!
I will keep such data only for long enough to administer shipment and any follow-up, and then very well secured with PGP Disk - but if you use Paypal or any other money transfer system, the record may be permanent and open for government scrutiny.
Cash (Federal Reserve Notes) is, however, still anonymous at this writing.