If I've already started selling tickets, and had to postpone the event because of something like COVID-19, I'd be looking at paying Stripe something like $3,500 in payment processing fees (it's 3.4%+$0.50 here; and assuming $100k in ticket revenue) for the privilege of refunding my attendees.

It's not an amount that would sink our non-profit, but the full fee is also not something that we should have to pay, just because we want to do right by our attendees.