Been in the game for a long long time and have never been asked to provide a deposit. That being said, I rarely participate these days and am highly selective and if it's a deal breaker then so be it. I don't need a paper trail.
I always follow cancellation protocols and one time when I needed to cancel inside a 24 hour time frame, I forwarded/mailed full payment.
Peace
MG
It would take a court order and a lot of work to track down who provided the anonymous gift card. And if you're worried about purchasing the anonymous gift card and leaving some sort of a trail on a credit bill, it's a $50 gift card. There are so many reasons for purchasing a $50 gift card. A gift to a friend, a gift for a relative, a gift for somebody work and so on. I'm not saying that the fear of leaving a paper trail is completely unfounded, but it is very remote.
I would also like to comment on the fact that if you found yourself having to cancel without good notice, you made good on the donation. You're a good man for that and should act as an example for others.
Bob