I don't have a problem with non-resort guests using the busses.
However, the argument that "what if they can't afford to pay for parking", IMO, is ludicrous. If they can afford 70 bucks a person to get into the park, then they can fork out 10 bucks per vehicle to park. If they are on vacation and staying off property, then if they can afford however much they're hotel costs, as well as their theme park admission, food, souveniers, etc, then they can pay 10 bucks a day to park.
Again, I personally don't have a problem if they take the WDW transportation. My wife and I did when we stayed off property and park hopped. Of course, in that case, we still payed for parking, but we just hopped a bus if we wanted to go to another park. I believe it is a service for anyone who has a park admission ticket (although we even rode the bus once when we didn't even have park admission, but that's another story. LOL). Just don't try to justify it with some cockenbull story about not being able to afford to park, when you obviously have plenty of money to go to WDW in the first place. :lol: