As an example of a a piece whose provenance is known, several additional verses which I have written have entered the canon, including one to "four nights drunk" which I slipped to Oscar Brand more than 30 years ago. A couple of years ago, he played his version and said that he did not know where he got the verse. I called him and reminded him of the circumstances of the contribution, which he acknowledged. Folk process or not?

I see development as a normal growth process. Another example is "Fiddler's Green," which has been cited on several albums, including one by Schooner Fare, as Trad. There is the ongoing discussion between the purists and the rest about "in Fiddler's Green" vs "on Fiddler's Green."

The list of discussions and processes is extensive. As long as people change things for their own satisfaction or through mishearing the process will continue.