You can park for free when dining at the resort, and they are supposed to ask for a receipt, but they never do. I am just telling you so you are not surprised if they ask for one. I show my DDE card when I arrive and tell them I am dining there, and it is never an issue.
And yes, I have left my car for longer than 3 hours, and never had a problem.
And of course, don't forget to tip!