"Craigie on Main requires a credit card to hold this reservation. If you cancel by phone 24 hours in advance of your reservation, OR if you cancel with less than 24 hours notice and we are able to re-book your table, there will be no charge. Otherwise, $25 per person will be billed to your card, and you will receive a gift card for that amount so you can dine with us another evening."
Okay, all is strong. But if a restaurant feels like they need to charge you tell them disaster occurs (and I'm sure there are people who lie), this is a brilliant way to handle it.