About 30 years ago I handled a quick swap, got one fellow a rifle he wanted and the other a shotgun. I knew both of them, some months later (after I had moved out of the area) one called me saying that the police had checked the shotgun and it was stolen. A couple of phone calls later it was straightened out. The shotgun had been bought new from a hardware store and the cops had a misfiled serial number on a stolen firearms report. If I hadn't been around to run it down for them a bill of sale sure would have helped out buddy number two with that shotgun. Just trying to say bad things sometimes happen even when everything is legitimate!