We take issue with it because parking has always been free to guests at the resorts. It is a recent change that those staying at the resort have to pay to park. So, if someone is driving over and has an ADR, of course they are getting free parking. I'm not sure who has said that guests will not be able to park there even if they have an ADR. Yes, it could happen, but it surely doesn't happen often.
Not sure what I said that makes you say this. There is usually plenty of parking for those staying at the resort as well as those with ADRs.
So, bottom line is...if you have an ADR, you will be able to park at the resort, unless there is some unforeseen issue. During extremely busy times of year (NYE, Christmas, July 4, for instance) you will have to have an ADR to be allowed into the resort lots. At other times, you may very well be able to park in the lots even if you don't have an ADR. As far as a time limit goes, there really aren't time limits anymore, at least none that are enforced. Now, that could change for these crazy busy days.