(is a new song folk if you sing it at a folk club? if Martin Carthy sings it? if lots of people sing it at folk clubs? No, no and no)

As a empirical pragmatist in such matters, and after long years of bitter-sweet experience in such matters even unto accommodating the MO of such stalwart Traddys as Peter Bellamy & Jim Eldon, I'd have to say Yes, Yes and Yes to this, and with some considerable evidence.