I heard a Source Singer sing an Adge Cuttler song one year at Whitby. When someone mentioned Adge as the source, the source singer said he didn't realise that that was so.

I guess this is the living tradition. Many of the people that Sharp et al collected from sang all kinds of songs, very old songs, popular songs musical hall songs and so on. Sharp had his view on what he wanted.

When did the term arise? Was it found useful because Source Singers sometimes sang songs that they learned from the oral tradition that were clearly, not by most definitions, either "folk" or "traditional"