Well, the only reason I posted to this thread is because I've never considered "John B." as "Trad" but I've had the same dossiers in front of me recently for the Weavers' cover of Linda's "Wimoweh." Not much different really.

In discography (in which I include sheet music, piano rolls, etc.) the "folk" genre/style is a consumer-producer tag. Without a specifc artist-listener-song it has little or no practical usage. eg: Based on a single discography Harry Belafonte is/was either America's greatest folk artist and/or a calypsonian imposter depending entirely on when, where and who is doing the talking.

"Traditional" is the credit for an unknown composer. The song need not be popular nor even familiar but often is. The set/setting for singing "Happy Birthday" is traditional but the song's authorship is not.