My father in law retired from the Marshal service and part of his extra curricular activities was raiding the Nashville Flea (the big one at the fairgrounds). He'd tell us that we don't know him if we see him there. They would go in, buy something from a suspected person and then have it validated onsite. After they were done shopping all the vendors they would sting all of the bootlegging vendors at once and shut the booth down and take everything there. He said every time they raided (maybe twice a year) they would shut down 5 - 10 vendors. So yeah, it happens everywhere and with more items than you would imagine. His group mostly looked for designer items like jackets, purses, jeans, shoes, sunglasses and watches. He said other groups would look for things like rugs, tools, toys, even furniture! A whole other group looked for stolen items. He said at any given time there were at least 25-30 undercover buyers from various agencies running around. He said the biggest give away that someone is bootlegging is that they have a lot of one type of thing like a booth full of designer Coach purses or the sunglass guy with dozens of Ray-Ban and Oakley or cases and cases of Tag watches. The ones selling 3-4 watches and then pans and some jeans and an old lawn chair, they were usually safe.