I think the reason for this is that the band always claims that they are not paid, but they are almost always lying. So, CBP uses some heuristics, and reasonabl

I think the reason for this is that the band always claims that they are not paid, but they are almost always lying. So, CBP uses some heuristics, and reasonably concludes that if a band is playing at a bar with an entry fee, they're probably being compensated. I am almost certain that was true in this case.