BB,I said it has never happened in my EXPERIENCE,[please quote me correctly]and as A revival performer for 31years, I have quite a large experience.
       many years ago,one of the traditional musicians I booked,clearly had no idea of Folk club etiquette ,and talked loudly through floor singers spots.I gave the musician preferential treatment[because they were a source musician],any other audience member I would have asked to be quiet,had another member of the audience complained about the talker I would have been forced to ask them tactfully to be quiet.,so it can work both ways.
Yes, I would agree with you Barbara.
Hopefully this thread may have acheived something, if it has made people aware that all performers should be treated well,and that the British folk revival has treated its source singers generally speaking in an exemplary manner,and often better than revivalist singers have been treated.