Nothing on the form mentioned the $50 extra fee.
We were presented a form to sign (after the shelter fee had already been paid) that had a liability clause with the word 'band' hand written in by the worker. When the band set up this year we were informed by park person that we had to pay an additional $50 for this purpose.
We always had a small band who played in the rented space. Rented picnic shelter for a family reunion three years in a row.