Earlier quoted context omitted.
IMNAL, My guess is that they can establish records of transactions they do with sellers and adhere to all transaction laws... but once they take possession of the good, they comingle it and can no longer tell where it came from.
That would be illegal. Imagine Pawn shop explaining to the cops they dont know which one of cameras/guns/rolex watches sold turned out to be stolen.
https://sellercentral.amazon.com/gp/help/help.html?itemID=20...