The Irrelevant Promise

This blog is written mostly tongue in cheek. Some points may be informative. Please provide your feedback.
If you suffer from self-irrelevancy, please seek professional advice.

Hello. As mentioned, my spouse and I are part of a large fundraising event. Each year we like to give last year's attendees first chance to attend again.
I've always been of the opinion this event should sell tickets like concerts and sports events. That is, people have to pay for the tickets. If they do, they're coming. If not, then they are assumed to not be coming.
My spouse and the other main organizer disagree. They say if someone says they'll pay, that's acceptable. However, it's been my experience this type of promise is irrelevant.
Why? Because a person could give us a credit card number, a post-dated cheque or a cash downpayment in lieu of the full dollar amount. Anything to secure their attendance. Our participants do not have any money issues, so this should be acceptable.
Then why isn't it to the organizers? More tomorrow.

Regards,
Irrelevant