I'd have refunded the money, just to be rid of patrons who sound like they're too dumb for folk music. I remember a concert in Central Park where the Rev. F.D. Kirpatrick was singing "Abraham, Martin and John" and added a verse that went "Has anybody here seen the P.L.O.?" I got up and walked out. It was a free concert (with others on the bill) but I wouldn't have asked for a refund if I'd paid; I'm all for his right to sing whatever he wants and mine not to listen. I never took F.D. Kirpatrick seriously after that but I doubt that he noticed.