Yesterday I stopped by the Chelsea bike shop on my way walking home across town and I came across a flea market in a parking lot, I think it was the same street, west 26th? Anyway, I thought I'd see if they had any old bikes for sale and turns out they had a few really nice bikes WAY in the bike almost in an alley (you wouldn't see it unless you took the time to weave through all the tents), there was a older canondale and some single speed bike and a few other newer really nice looking bikes. It felt kinda shady and I wonder what's the chance that these are hot? Probably pretty good right? On my way out I also saw a really nice looking rim hiding under a cover, I thought that was REALLY shady, I mean who covers up a bike at a flea market?
Anyway, maybe it's a good spot to look for your stolen bike, or maybe a good place to find a deal. Not sure but I don't think I'd feel good with myself for buying one there, unless maybe it was just some junker (which is what I was looking for in the first place).
The brownstoner.com flea market in fort greene also has a guy selling bikes. He didn't have anyone that looked especially expensive and he just might be buying them on craigslist, but in general it is hard to know the precedence of the bike when buying in a flea market. It is sad because they might be a legitimate business, but due to the huge number of bikes stolen every day, they turn out to be the target of suspicion.