[not_the_fda]

Yes the places that buy used books respect the stamp. They usually take all the books and take them to some place Half Priced Books https://www.hpb.com/ for some quick cash.

Places like that won't buy them if they are stamped.

They could try selling them on Amazon or E-Bay, but that's too much effort for quick cash to get a fix.

[PacificSpecific]

Thanks very much for the info. I'm building one now in a city with a fairly rough drug problem and I had no idea the stamp existed.