From Roud's Introduction: ""... instead of asking "What folk songs did people sing?, we are more concerned with the question "What songs did the folk sing?".

Roud stopped at about 1950. In times to come Jack's woman on the bus leading Caledonia, with a smartphone as a prompt, will be part of what the folk sang. Part of the social history of non-for-money singing by 'the folk'.

I think there is an argument that my childhood experience of people on a works outing singing (probably) Music Hall and WW1 favourites on the back of a bus is closer to the folk's music than a folk club on guest night.