" adaptation, development & improvement"
I totally disagree with this Vic -at least until it is backed up with documented evidence rather than opinions
Baring Gould, Sharp, et al were working when the tradition was in sharp decline and there in so record whatever of them treating collecting songs as artifacts, the way a butterfly collector regards his trophies.
Sharp came the nearest with 'Conclusions' and there are a couple of nice quotes in Fox-Strangways to suggest that he felt a warmth for some of his informants, but one of the greatest holes in our knowledge is the lack of an input by the singers.
I'm afraid thisis beginning to feel like a return to the 'free as Bird Song era'
This is one of the most offensive statements I have ever come across from someone who really should have known better, a note to Lake of Col Fin from "the Vermont collection, New Green Mountain Songster by Phillips Barry in 1939:

"Popular tradition, however, does not mean popular origin. In the case of our ballad, the underlying folklore is Irish de facto, but not de-jure: the ballad is of Oriental and literary origin, and has sunk to the level of the folk which has the keeping of folklore. To put it in a single phrase, memory not invention is the function of the folk".   
JIm Carroll