Places like California Grill require a credit card guarantee and if you don't cancel in advance and don't show up you will be charged something. CG has a two day cancellation policy and the charge for a no show is currently 20$ per person.
CRT, on the other hand, charges the full amount of the meal at the time of booking. They have a one day cancellation policy and no shows are charged the full price of the meal. I assume if you cancel more than one day in advance you will get the money back on your credit card.
If you book online the policies for each restaurant will be outlined when you add them to your cart.
For the majority of restaurants there is absolutely no charge for making an ADR or not cancelling if you don't show up. However you should always cancel if you change your plans to free up the spot for others.