That's fine for 'folk' but not for 'traditional' becuase what happens is people put 'trad' on their CDs and then, because 'trad' has a legal definition, the work's ownership can become lost, and rightful payments not made.

It's happened scores of times and its very hard to re-establish ownership once lazy people have committed this crime - and yes, it is actually a crime in law. It's called theft.