There's the question then of whether tunes were ever "traditional" as a separate type as distinct from a matter of intellectual property- look at Richard Robinson's music pages- all the collections seem to give a mixture of tunes which are traditionally traditional, ones obviously composed for particular occasions or locations ("The Long Room at Scarborough"), fashionable tunes that probably only got played for a season or two, ones wagged from operas and plays, etc. It doesn't look very different from what players are doing now, though we obviously have little idea of what musically illiterate players were doing.

I find it amusing when some players start getting all officious about certain tunes- the Calliope Jig is "really" called Calliope House, and "must" be played in A because the composer intended it that way- ignoring the fact that in a session milieu tunes are like children, once they are out in the world their life is their own.

Song tunes may or may not be another matter- I don't see anything wrong with, for example, singing Lakes of Coolfin to Dave Burland's Keepers and Poachers tune tune.