The expectations of the audience, THAT IS MY POINT.
If you turned up for a Martin Carthy gig, it will have been promoted in a certain way, you will be expecting a particular style of song, if you turn up for a Jim Bainbridge gig you know what you are likely to get, if you turn up to Leon Rosselson you have expectations, no one needs a 1954 FOLK Defininition to decide whether an artist is their particular taste to make a decision about attendance.
so another point is that as soon as people start to charge money thee become expectations.
Charlie Stringer sang as a non professional he was classified by John Howson who was in the business of becoming a collector and wanted him to be part of his old hat party and be a "traditional singer" ,but Charlie, just sang what he like, an old ballad one minute a country and western song the nex,,
you know as well as i do that traveller "tradtional" singers the sort you collect, do precisely, this they dont care about definitions they sing exactly what they want, country and western and/or old ballads, they decide upon their songs not upon classification but because they think the song is a good song.JIM BAINBRIDGES Point
this in my opinion only changes when people start to make money out of it and start to have an image and an audience starts to have expectations.
if paying people turned up to a Carthy concert and he sang Lonnie Donegan songs all night, they would be surprised and probably shocked, and might ask for their money back, but it would not be anything to do with the 1954 definition.