I was once at a folk club night that featured John Roberts & Tony Barrand.
During the interval a female member of the audience approached John and said "In the second half, could you ask people not to join in on your choruses, because I came to hear you - Not them!"
John (I believe), was at a loss for words!

What killed the folk scene for me in England (many years ago) was the gulf that occured between the audience and the performers. To many "Them and Us".
We even had to close a folk club once - not because we didn't get an audience or that we ran out of money (we gave our surplus to charity) - but because we didn't get floor singers to support the guests!

Tim Radford