If you really want to get to WL and not park at the TTC, you can park at DS and bus over. Even though WL often shares a bus with the CR, it's usually the first stop off.
As others have mentioned, I'm of the inclination this may also be security based as well, not just parking. At DLP, the whole resort is basically a security bubble, including hotels. WDW has been moving in that direction, so it doesn't surprise me they might be clamping down who's parking at the resorts, especially those close to the theme parks.