This probably will just muddy the waters further (or is that blues) but I have the following thoughts.Seems like Elsie's analogy between the field of collecting physical items and music might be helpful. I think she is saying that folk = antique and "pseudo-folk" = collectibles.
I think Laoise might say folk = "Antiques and Collectibles" (or whatever overarching category exists among collectors) and "trad folk" = antiques.
If you look at it this way you see that people ARE using the same word for different things. In this case they are using the same term for different levels of a hierarchical categorization of music which makes agreement REALLY difficult.
HOWEVER we should keep trying because this ISNT a general music site and does need exclusion/redirection criteria.
Elsie is right about stray cats at the door (even using the broadest definition of folk). I also think that the best strategy is listing an alternate site wherever possible. From my limited recollection of Psych. 101, I think "Scram" probably won't be as effective as "Let me show you a REALLY good source of food."
Frank Phillips