Hi, Piers Plowman - I think Lee Hays (1914-1981) of the Weavers and other groups was a singer who sang what worked for his audience, not what might be absolutely correct from a historical standpoint. Many of us think that's a good thing. In performance, music must primarily be for the audience. All other considerations should be secondary in performance, but perhaps they should take a more important place in research.
-Joe-