I'm being relatively flippant in this post.

We have a chap who comes and sings and plays sometimes at our gathering. Every now and then someone will sing a song and he'll lean forward and go 'what's that called?'

Usually about three - six weeks later the song reappears with a different tune. Is this part of the folk process? To me 'Mr Punch and Judy Man' and 'Summer Before the War' are both fine tunes that don't need re-writing but it's good to see that the tradition of partially remembering things and then doing them differently still exists! :)