There was a news clip a week or two ago about a bunch of bad 50 and 100 bills going around in the area. Washed (bleached) 5 dollar bills that had been reprinted. So it may be that the guy who "spent" it at the swap didn't even know he had a bad bill. But it's ALWAYS a good idea to look at the embedded strip in larger bills and make sure it reads the same amount as the bill is printed for. And another tip, the strip in each denomination is in a different location so you can readily tell a 5 from a 20 from a 50, etc. just by the location even if you can't make out the print on the strip. But you wold need to know where those spots are so just hold the bill up to a light and read the strip.
There is a fish fanatic passing counterfeit $50.00 bills. I got one at the Milwaukee swap yesterday. I don't know the guys name but I would certainly know him if I saw him. I've seen him at all the Milwaukee swaps and I am pretty sure I have seen him at the GCCA swaps as well. I'll be more than happy to pass on any information to anyone who is interested but I will only do it through e-mail. I will not post any information on this site nor through PM. If you are interested send me an email, if my email is not in my profile (I'm not sure if it is or not on then site) then send me a PM with your full name and and email address and I will tell you what I know about the guy.