In the USA, it was notable that singers you might think of as "source singers"(eg Woody Guthrie and Leadbelly) actually got a lot of material from the collector Alan Lomax, printed sources etc. I dont quote this fact to denigrate their status, far from it. Leadbelly and Guthrie didn't get their style from any collector, or out of any book. They were the real thing, actual folk singers. But they certainly topped up their repertoire from sources quite different from the simplistic vision of the oral tradition.
    This sort of thing happened to me, it is perfectly commonplace. For example, I come from A Cornish mining family, and my grandfather sang me the Sweet Nightingale when I was little. I just sort of filed it away in my mind.Fast forward ten years, I heard someone sing it in a folk club, realised I knew it, decided to sing it, and brushed up on the words from Baring-Gould's "Songs of the West Country", a book given to me years before, as a child. So, am I a traditional singer when I do that song, or a revivalist? The relationship between tradition and revival can be very complex.
    Having said that, I am certainly not one of those who think there is no difference between the tradition and the revival. There is a huge difference. It's just that the relationship between the two can be complex and not all one way.