Jim sorry, I wasn't meaning that the songs should be written down and put in a big stack never to be looked at, but rather that we (them that can sing and are blessed with a good memory for the words, that is - which is not me, these days I can't always remember the right "B" part to play) should be able to perform them pretty well as they were sung when they were collected, as well as giving our own "take" on them. A counsel of perfection, unattainable probably; but something to aim at. And well understood by wider society, with tribute bands, cover versions and someone elses arrangements.
The other side of that coin of course is that if we keep that original form too strongly in our mind, the almost random variation that is the "folk process" doesn't have room to operate, and the only variation that occurs is deliberate, a totally different thing.

And - of course we should keep singing and playing. And hopefully derive a great deal of pleasure from doing so, however imperfectly. How many times have I argued in this forum that the important part of a "folk festival" is the informal gathering in churches, halls and pubs where we sing and play together, talk, drink, and maybe sometimes think. And perhaps pass on our enthusiasm and love of music to those who stop to listen.