What, between singing and listening??! Huge physiological and psychological and differences, surely?

The communal experience of music exists in terms of its performance, social context and function, all which determine the meaning of that experience with respect of the individual and the others in the community. Even the playing of records is in itself a meaningful performance & an essential interaction between performer & audience. We all do it, even the most folkie of us. Hell, how else would I get my daily fix of Brian Peters or find renewed levels of meaning therein even in the same recordings?

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But the words don't change and the tunes don't change, and one song doesn't turn into two or three different songs. That's why I don't call them folk songs.

Songs change the whole time. In the process of composition there's more than the one song as found itself split into two or three songs, and vice versa of course. The musical process of composition & creation will forever be a complex and intricate procedure in which definitive versions will rarely exist. There are innumerable instances of this; just last night whilst cooking dinner I was comparing the various versions of Robert Wyatt's Moon in June which begins life as two distinct songs, morphs into one big one, loses most of the original lyrics in the process and has the new lyrics completely rewritten for a BBC session. Other example abound. Otherwise - I refer you back to specious criteria.

I am not denying, have never denied and would never wish to deny that lots of different musics are known to and cherished by ordinary people, let alone that they have meaning, function, purpose and relevance. This has sod-all to do with whether they're folk songs.

It has every reason to do with it. Take the Folk out of Folk Songs and all you have are songs relevant to a dwindling body of Enthusiasts of a Particular Type of Folk Song - Traddies in other words, like me, and you, the difference being that my main interest in these Traditional Songs is in terms of their humanity and what they might tell us about ourselves, rather than some quasi-mystical process by which they supposedly came into being. Technology changes, but a fishing boat is still a fishing boat, be it made by the master shipwrights on the shores of the Sea of Galilee circa AD 20 or by the lads on the Jubilee Quay in Fleetwood circa AD 2009.   

Yes, you've demonstrated that the 1954 Definition can be read in such a way that it encompasses all music ever. However, since the 1954 Definition obviously wasn't intended to encompass all music ever, all this demonstrates is that you're misreading the definition.

What it demonstrates is the redundancy of a definition that only makes sense with an Orthodox Reading by the Folk Faithful (or otherwise initiated). Without it, what you have is a fundamental description of the process by which people make and experience music in communities, and whilst this might find an echo in the aims and objectives of the ICTM, it leaves the ninny-nannying of the 1954 Orthodoxy seeming sadly anachronistic to say the least. Hardly the wonder the Orthodoxy of the Folk Revival is an ageing, dwindling, whinging demographic poised on the precipice of extinction; with such a poisonous orthodoxy in place it's a miracle that it's made it as far as it has. Real Folk Music meanwhile - the music of every day people living every day lives giving meaning to their every day experiences - is, and will always be, thriving.