Originally Posted by Sweet Willie

I'd like to see a credit card commitment for reservations. While sure there are some true mishaps that cause someone to completely miss a reservation, I think I'm very safe in assuming that the majority of missed reservations are due to people's selfish or forgetful nature.

Knowing you'll be dinged for a no-show will change some (most?) people's bad behavior.

As far as stopping some diners from booking, if the restaurant is producing quality food and has the demand, the restaurant will do fine regardless if some diners won't book due to a credit card ding for not showing up.