I always do a BOS. Because if the cops ever come to me and say that gun was used in a crime (they say there's no registration but you always hear about them tracing the gun all the way back to the gun store that originally sold it) then I want to be able to give the cops the guys info to eliminate myself as a suspect.
ROFL
A paper trail you sold a gun used in a crime. Yeah, nobody has ever been sued out of existence over that...
Nothing, and I mean nothing, beats an anonymous sale.