This is Your Brain on Dope

I assume they realize all their customers are "prohibited persons" per federal law...and they've fully informed them of that fact? [More] 

Be an interesting lawsuit, when someone claims they had no idea they were trading in their rights, and that the "dispensary" knew or should have known to issue a legal warning before registering their purchasers.  I'd love to see someone propose a law mandating such warnings be both posted and acknowledged by signature on each transaction.

It figures "progressive" dopers are statist pigs, partnering with the "Only Ones" to ensure a monopoly of violence. Opposite Day 'n all that.

And in answer to the question of how such transfers are "legal," here's the answer I got from BATFU back in 1999 when I asked:

ATF has no objection to State and local gun buy back programs. However, we are not participating in any such programs at this time. We recommend that if law enforcement officials conducting such programs come into possession of a firearm subject to the National Firearms Act (NFA) 26 U.S.C. Chapter 53, they contact their local ATF office for assistance in disposing of the weapon. NFA firearms include machineguns, short barrel shotguns, short barrel rifles, silencers, and certain concealable weapons.

[Via Jake S]