This is really pretty simple...you are entitled to park, for as long as you want, at the resort you are staying at. If you wish to go to another resort, and eat there or even swim (if a
DVC'er) or shop? You are more than entitled to park there for the time you are using the amenities of that resort. Same goes for BLT and heading up to ToTWL.
BUT...you are not entitled to park at the Polynesian (for instance) have breakfast at 'Ohana, and then head off to MK for the day.
Nor can you self park at BW and head to Epcot for the day.
It's really not fair to those people who are paying good money (or using points) to stay there and avail themselves of certain perks...for instance, easier access to a park.
So, go and eat and shop and maybe even have a swim at the Polynesian. But please don't feel entitled to just self park your car and leave it there for the day. Really not too fair to those that are staying there to have to take parking spots further removed from the more desirable parking spots.
Do they tow? Sometimes, but not all that regularly. I have sat and watched in the morning from my balcony at BLT...kind of interesting really. I watched as security drove around the BLT parking lot around 8am...then again later on. They watched which cars had parking passes displayed. They took down numbers (I'm assuming since I watched them take out a notebook and write something down if no pass was displayed). Then, they would return later in the day...do the same thing. But I never saw a tow truck in there.
If security/Disney wants people to park for just three hours, then they should start giving out 3 hr parking passes again. They go on the dashboard in order to be seen. But, obviously there isn't a lot of concern.
And yes, you can pay to valet park for the day and no one will care where you go.
The way I figure it? If you're heading to the Polynesian for breakfast and then over to the MK for the day??? Park at the TTC and either walk or monorail over to the Polynesian and eat, then head to MK for the day. That's the 'right' way to do things.