"they [travellers] are major contributors to both our pleasure and our knowledge"

I don't see how anyone with a knowledge of traditional singing could dispute this comment of Jim's. Not only have traveller communities maintained old ballads in oral tradition long after settled communities abandoned them, but their versions are full of departures from 'standard' texts and often have really interesting tunes. Go and listen to Caroline Hughes - I don't think there was a broadside in sight when she learned her repertoire.