Will, there is ambience and there is noise. I've known both - sometimes the same venue on different nights. While there may be little one can do about, as far as I'm concerned, when the background has reached the sort of level where you can't hear Irish pipes 3 feet away from you, I think it's got too much...

As for occasional requests. I think an Irish dance tune that hadn't already been played and was known to some present, there would be a good chance of it being played.

The sessions aren't likely to move away from their Irish instrumental aims though and a request is more likely to be for a song like Wild Rover than something that fits in.