Soldier boy, they are interesting points.

There's another side to the coin too, though. There's a pub in Dublin that's ideal for a session, because the room where the musicians play is partitioned off, so the music isn't heard by the punters who may be watching television, and vice versa. The small group of musicians who meet there are very good, but they tend to play tunes (Irish) or songs (American--sixties or old timey) that hardly anybody knows, and they do not encourage others to join in--THEY are the performers. So what could be an interesting evening ends up with just the 3 or so musicians in a corner playing to themselves, which is a waste of good talent and of a good venue (in my opinion).