No, you are only charged DDP credits if you actually eat at the restaurant.
The only exceptions may be CRT, Spirit of Aloha and Hoop De Doo Revue since these are prepaid. If you don't show, you would be charged either dining credits or credit card charge but that is for everyone (DDP or not).
I believe that there is also a charge for no shows for the Fantasmic package as well as the Princess Storybook dining in Norway as these are all credit card guaranteed.
Except for these few places (basically if you need to give a credit card when you make the ADR either show up or cancel ahead of time) you don't have to worry about not showing for an ADR. there's no penalty.
But, PLEASE, cancel if you don't need it! Others are often searching for dining times and it really bites if someone can't get a spot but then people holding ADR's don't show up.
Thanks and agreed - I would try my best to cancel. I have made my ADRs based on where I plan to be. There is only one that is a 'kinda' as we will be in AK and DS likes Rainforest but I managed to get an ADR at Coral Reef which I thought he would enjoy - but if we don't feel like haulin' it over to Epcot I may cancel that one....just wanted to make sure if I forgot I wouldn't get dinged.
I agree -- please, please cancel the reservations. Even if you call the restaurant very shortly before your reservations. Somebody might walkup to the restaurant and be able to take your table.