I think LesB misses an important point in his comments regarding people who go to festivals and don't pay in to concerts; thereby "in some way not contributing "to the running costs of the festival.."
I had a similar discussion/argument with the organiser of a new and well attended festival in Scotland about four or five years ago.
If all you do is want to make money then run concerts and hope that you will get enough people to attend thereby covering costs and making a (usually fairly small) profit. But all you will have will be concerts, not a festival.
If however you want a festival...then encourage the non-payers to turn up. We non-contributors will sit in the pubs, drinking, eating,(thus providing income to local businesses who in turn may give suport to the festival) singing and playing tunes which in turn will (hopefully) encourage others to linger in the same pubs.
I am tired frankly of being told I don't contribute to festivals just because I don't buy weekend tickets. I don't buy tickets because I'm not a fan of concert type settings for folk artist and besides I'm too busy enjoying myself in the sessions with my friends but if you think that is non-contribution then come along and see where the festival is really taking place and go to the tune sessions and see where young folk are because the chances are they're not in the concerts either.
I am not attacking those who only go to concerts and can't abide sessions nor am I atacking those who buy weekend tickets and attend everything, sessions included, where possible. I am however defending those of my ilk who choose to do their own thing in the pubs and who add to the indefinable ambience of a successful folk festival..