I saw something similar in Whitby on Sunday when an a capella duo asked the audience not to join in the chorus because they did it differently and the audience joined in (and part buggered up the song for them) anyway. I sing the Blue Cockade which is different from the White Cockade (mostly in terms of word order) and I nearly always remember to ask the audience not to sing the White Cockade, but whether I remember or not there is always someone who joins in (invariably singing the white cockade). Seems a folk audience just can't resist. Changing the key on a singer though is just plain boorish and I'm surprised the singer didn't object; to be honest it sounds as though these musicians were extracting the michael. F