The 'folk process' is not just "individuals, making a choice about what they will sing" - it is ALSO the audience response. When a behaviour (in this case a song rendition) is 'rewarded' (recieves approbation) by an audience, then the likelihood of its being repeated is increased. If the reverse, the likelihood is decreased. This is the way in which the text becomes 'honed'. This is the (only)way in which the community (en masse) 'creates' the song. This is, I would think, going to hold true whether within the (no longer existing) traditional communities from which the songs were collected - or from within the modern communities of interest (although nowadays, of course, we have promotion, publicity and hype to tell us what we should approve of.) Then, just to complicate things further, many of the ballads we're talking about here were not (but I won't say never) performed FOR an audience - more often within a domestic, even solitary, situation. It is the folk revival that has created a'new' context of performance.