If they play one song continuously for more than fifteen minutes, and they're at a folk festival, they're either old-timey musicians, traditional ballad singers, or people showing off their knowledge of Dylan lyrics. If they were doing "Sail Away Ladies" they were old-timey musicians in their heads, even if they were getting a bluegrass sound.

Just so long as they weren't drumming. A few years ago I almost took the hatchet, that I brought to pound tent pegs, over to a drum circle. But that's just me.

Peter.