I may be naive, but I thought that festival organisers booked the acts that would guarantee them an audience.

Then I thought that the the organisers filled the bill with cheaper new acts, thus giving these new, possibly lesser known, acts a chance to perform in front of an audience and possibly getting the recognition that they deserve.

I think that if the people who Lizzie mentions were headliners, not many tickets would be sold. I agree that this is wrong - but it's business. George Papavgeris and Duncan McFarlane played at Shrewsbury this year. They weren't the headline acts. If they had been, I don't think the audiences would have been so huge. Because they were playing in front of the big audiences that had come to hear Seth Lakeman, SOH and the like, they gained themselves lots of new fans.