Surely 'tradition' is defined by usage, not by whether there is a known composer.

It is 'traditional' to sing 'Happy Birthday' on the occasion of someone's birthday; it is 'traditional' for Will Noble to sing 'The Mistletoe Bough' at certain local gatherings; there are certain occasions when it is 'traditional' to sing 'God Save the Queen'; local to me, there are a couple of hunting songs 'traditionally' sung by the hunting community, both of which have known origins, one from the early 1900s, the other from the 1970s; certain songs are 'traditionally' sung by the participants of the Haxey Hood game each year.

The community defines tradition, whether that community is the whole English-speaking world, the citizens of a country, or a locally-based group.

On reflection, I'm not sure how much this actually helps us in defining what songs are traditional and what are not, or how the folk revival singers are able to continue the tradition, unless they now carry them within the 'folk community'. Maybe they do, and hopefully take them back out into their local communities. Don't know - just meandering in my mind and here...

Barbara