I think the Traditional Music Authenticity Police (TMAP) have a sister organization, the "You played it differ[e]ntly" police (YPID).

The only way in which I would differ from John P's fine analysis is that the two organisations are actually one and the same. The two attitudes both spring from the unshakeable conviction that the AP member has a very fixed, rigid, Gold Standard idea of what is traditional & correct and what isn't, has a much better idea of what is traditional and what isn't than you or me, and also has a messianic drive to share that knowledge with us for our own benefit.

There was a virulent outbreak of APism on concertina.net recently, in which it emerged that the basic premise was that playing a tune on anything other than a solo fiddle was not proper Irish Traditional Music. Which makes you wonder what that particular high-ranking member of the AP was doing on concertina.net in the first place, since the clue's rather there in the URL ...

Martin Carthy, the man already outed as an AP offender for playing the guitar for Morris, makes a wise observation - I can't remember the exact quote but it paraphrases as 'the single worst thing you can do to these songs is not sing them. They will survive everything except neglect.'

There's a lot of stuff done to traditional music that I, personally, don't like or enjoy. But, unlike the AP, I always try to remember that my personal taste does not equate to the evolution and health of the living tradition.