Again not the worst example, but:

I normally go to (what I call) sessions (where everyone joins in together if they can or want to) - or singarounds/playarounds (where everyone takes it in turn to play and/or sing on their own). These are what I'm used to.

But a week or so back I went to what seemed to be a combination of the two: it was a round-the-room singaround/playaround, but there were a few people there (guitarists mainly) who seemed to join in with everything everybody else was doing, even when someone was singing unaccompanied. This seemed to be the normal case, and nobody seemed to mind. I found it a bit odd though, and found it difficult not to wish they would shut up when I was playing. I refrained from saying anything though, because this was apparently how they do things there, and who was I to argue? Didn't like it though.

Is this normal in the experience of others? It was a first for me. Does anyone think it's better than the two scenarios I described above?