We had one singer singing a song about a bird singing in a tree.At this point a person in the sing around started playing a bird warbler.Although the singer was clearly getting upset he persisted with it.With two verses still to go the singer picked up his drink and through it over the Warbler.He missed and drenched the poor chap by his side.That singer has not been seen again or his wife who is a joy to listen to.Thinking about it the poor chap that got soaked has not been seen since.
The other thing Jim ,similar to what your saying, is that singers will sing the chorus of the version they know which may not be your version. Another problem is that during your song some anticipate your ending and do a long closing note. This is very off putting particularly if you have a number of verses to go.Instead of shutting up they continue to try and close the song.I love people singing along with me, but I wish they would just listen to what I am doing.
Alan