In terms of people actually playing in tune sessions, my experience (as an observer, as my melodeon stutterings can hardly be called "playing") is that the players don't seem nearly as interested in the provenance of tunes as singers of traditional music are. I don't know if this is more the case with a younger generation of musicians, but it's certainly my experience that if you ask some of them the name of a tune and where it came from, they just shrug their shoulders - they just play the tunes that catch their fancy. I know someone whose been in a couple of prominent bands who has heard one of his own tunes creep into the repertoire of another band - "It's become one of 'their' tunes; I don't think they even know that I wrote it!" he said.

So I guess what I'm tryting to say is that, in practice, it seems a much more fluid and organic line than the more rigid divide we sometimes observe between traditional and contemporary song.