One of the best Irish Tenor banjo players around, Kevin Griffin, is actually from Doolin, and I've long since thought that he should patent that particular name.

As far as I know there's nothing particularly "correct" about using fiddle tuning GDAE for Banjos, but most people use it because it is fiddle tuning and therefore makes it easier to switch from one instrument to the other. As far as I know Gerry O Connor from Tipperary uses a different tuning, at least for some tunes. (I think its an open C tuning but I'm not sure). I've heard was actually a more standard tuning than fiddle tuning in earlier years, but you hear lots of things.