There does seem to be something of a contradiction in the position of the AP. If they accept the 1954 definition (which I would have thought axiomatic for them) then it follows that the songs and tunes in or coming into the class must have changed and continue to change, and simlarly the methods of performing them.

I think some folks lose track of the difference between traditional and historical. I once was in a drum store and overheard another customer telling the owner that "traditional bodhrans don't have bars across the back". I decided not to get into it with him, but since I had been playing with very accomplished bodhran players for years and had only ever seen (at that time) one drum without bars across the back, it made me wonder at what point in history the tradition stopped for him.

The problem with using history as a cue to correctness is, of course, the cut-off date. If you go back far enough, you end up with nothing but voices and maybe crude drums. I was once told that my guitar wasn't a traditional instrument and that I should stick to playing my Irish bouzouki -- an instrument that was invented about 40 years ago.