As Aimeedyan said there are a few places that will charge if you don't give notice. The dinner shows require a 48 hour notice (this is what I was told when I booked the Poly Luau thing recently) The Princess breakfasts also need a credit card hold, and want 48hrs notice of cancellation (again what I was told recently in regards to Akershus) When I last went to the Contemporary there was a $10 deposit, I can't remember the time frame for cancelling for that though. Also Victoria and Albert has a $25 (I think) deposit, looking at my ADR notes, I have a 24 hour cancellation policy for that. It seems to be the signature restaurants that have some sort of policy for cancellation. Though I do have an upcoming ADR at Narcoossee's, but don't remember them needing a deposit.
I really don't know how accommodating they are if you are an hour late. We've been 10 mins late, and that has been fine. We were driving down one year, and we were late, and were just not going to make our Yachtsman ADR, by about an hour. I did call an hour before, so as someone else could have our spot. I really didn't expect them to seat us an hour late. It was a nightmare that trip for unplanned dinning, it was so busy and this was November (Jersey week, Soap weekend, F&W all collided)