Lepus,
I don't know the ins and outs of copyright law. (You probably do.) My point is to acknowledge the authorship of the new lyrics--not the ones that overlap with the public domain song or their match to the tune. As with other songs posted in Mudcat, the aim is to prevent the eventuality of someone else claiming copyright to one's own words and potentially preventing one from even using them. It has happened before.

The intent is by no means to 'steal' something in the public domain.

Jeanene