Recently someone showed up at a venue saying that because of his level of donation to the performers Kickstarter CD campaign, he'd earned two free concert tickets. He showed the person at the ticket table (not me, but I was standing nearby) an email from the performer verifying that. The performer was doing soundcheck, so the ticket person let the man and his companion in. Later she asked some board members how this should be handled in the future. This person could show that email at another venue; the email didn't specify a venue. One board member suggested that at the end of the evening the amount the venue should have earned could have been deducted from the performer's pay because he, not the venue, gave away the ticket.

Who has had experience with this as a performer who promised free tickets during a fundraiser, as someone who has earned free tickets by donating to a fundraiser, or as someone has experienced this while working at a venue? How is this usually handled?