I believe that many folkies began saying where they learned songs in order to share the glory of field collectors who are required to name their traditional sources, partly as a guarantee of authenticity.

Hardly anyone says, "I learned this from a record." Too boring. But "from the (heh-heh) singing of Jeannie Robertson" - WOW!

A "sense of tradition" is far more to the front in "folk" music than in other genres. Without it, many songs lose their interest. So expect some people to fudge.