I think you are far more likely to get paid/validated parking at DTD than you are to have the SSR grounds restricted. Disney doesn't restrict grounds at any resort, they DO have paid parking lots. I think grounds restriction would be a huge shift for Disney to contemplate - and cause a lot of issues. Disney resorts are destinations onto itself - resort touring at Christmastime is a big deal, plus the restaurants and shopping at Disney resorts, add in that anyone can go rent mouseboats over at WL or do the pirate cruise at the Y&BC or fish out at POR. And Disney likes having that sort of resort access - it convinces people that their next stay should be at one of those resorts.