I remember long ago [at the very 1st Cambridge FF, 1965, IIRC] Jon Raven & his group The Black Country Three [I think they were called] sang The Bonnie Lass Of Fyvie; & Jon in his intro saying that they always sang the second verse ['Mony a bonnie lass in the Howes o' Auchterless...'] as a chorus after each verse, "because we find people like singing choruses". That is a song with a good bouncy tune, and it seemed a good idea; and no-one obtrusively then took it on themselves to join in with the other verses, even tho most of us knew them. It is surely a matter of courtesy to take one's lead from the performer[s] in this particular.

~M~