Marge, that's why it seems so much more accurate to refer to them as 'song carriers'.
So you learn a song off somebody's CD. That's still 'oral tradition'.
The only reason why a much earlier 'source singer' didn't was that they didn't have electricity. Or CDs.
'Drawing a line' is by definition arbitrary.
You might as well say (and there are those who do) that those who don't sing a ballad exactly as the first person to write it down (and many a time that version has been disproved from a later-identified printed source which pre-dates the 'collection'), are not getting it right.
In fact, once the performance of ballads loses sight of its purpose which is, first and foremost, to tell a story and in doing so to continue and add to a cultural heritage, the plot is lost.