General, Sir!

If a song or tune is accredited to "Trad/Anon" and it's still in copyright, the composer or his/her heirs get no royalties. Nowadays you can PRS/MCPS-register your work who will try and recover what's due to you but many still slip through, as in the scores of Irish singers who claim something called Shores Of Erin (y'know, that one about sailing round the coast of Ireland) has been in their families for centuries and no. they've never heard of Ewan MacColl and Shoals of Herring). And then there are all those which musicians have researched from disuse and obscurity and arranged that chancers pick up, usually with inaccuracies, record and pass off as 'Trad' instead of 'Trad. Arr'. The (Monde)Black family is especially notorious for failing to acknowledge secondary sources and arrangers.