DtG: I think we may be at cross purposes then, Gerry! I know that Rob said session which I think was the point - It was an open session and the young couple heard and liked it. Your point, and correct me if I am wrong, is that they would not have heard it if it was in a 'dingy back room', which is quite true.

Yes, that's it exactly...they wouldn't have heard it if it had been in an opulently-decorated bright and cheerful back room, either! Pub sessions and other "open" events are the places you'll see the music exposed to newcomers, not "folk clubs" in back rooms (dingy or otherwise!) which are preaching to the converted.