Dave,
Sorry to be pedantic but the majority of us decided at least 70 years ago (I think even dear Cecil agreed in the end) that knowing the writer/composer was irrelevant to any of these meanings or words, other than the word 'anonymous'. As you have brought this old chestnut up we need to refer back to the dreaded 1954 IFMC definition which quickly decided, with input from a large number of foreign delegates, that this part of the definition was irrelevant and should be deleted, and forthwith it was. Otherwise all of those Harry Clifton songs I have recorded from oral tradition will have to be excluded.

To repeat something that has been said on this forum ad nauseam, the definition isn't perfect but it works well enough for most of us doing the research. What the singers do with it is their business.