I've never been to a bad folk performance, but I went to awful performances by Bob Dylan, by singer-songwriter Shawn Colvin who blamed her nastiness on PMS, and one other one that just slipped my mind - oh, Bob Hope. All three treated their audience with disdain, and all three gave poor performances. I think you're just as likely to get a bad performance from a big-name performer, as you are from an unknown.

-Joe-