Susan,
You have encouraged people to think about and discuss a very interesting and vital topic (IMO) and that in itself is of value.
Despite some of your more romantic notions you have inspired me to go back now and have another look at all the different variations of this motif. I mentioned the possibility that the motif has come to English in translation perhaps on different occasions and I now want to pursue that possibility. I am deeply interested in motifs and commonplaces.

Regarding 'Scotch' songs, I have read on more than one occasion that to the London Society world of the 17th century anything from 20 miles north of London not in standard English was referred to as 'Scotch'. I probably read that in Child but I couldn't swear to it.