Heh. The Virginia gun shows have a low idiot population in my experience. At the last one, the worst was a guy selling some "miracle glue! It's cyanoacrylate, but it's different from superglue! Honest!" I got a post-sunset rifle there... for $800, a Bushmaster no less. The prebans topped out at $1000 if they were in pristine condition, more if they were special (like the Colt LMG upper with the square handguards and heavy barrel, $1200, no lower unfortunately, and you would have to replace the internals to be compliant). The worst that ever happened was a guy that tried to sell me a regular CZ-52 with original barrel as 9mm. Moved on.
Or it could have been the guy that sold me an M91/30 for $100. I thought it was a good deal, though, so it was me who was the stupid one. Now the bore's rusted out.