I guess this is a feather in BLT's cap, as it is within walking distance to the MK.
As for parking at DTD, I wonder if they could have an open entrance but a pay to leave type system. If it is a flat fee system, a machine could be used to accept several types of cards: credit card (for those who pay), a standard parking ticket (given by a shop or restaurant as vaildation or if the guest pays the parking fee at the store), a KTTW card, or an annual pass. The store passes, KTTW card, and annual pass is likely coded with an expiration date (and time if used at a resort hotel), so the gate will not work if the card is expired. If a valid guest has to use a credit card due to an error, they could simply bring it up with their hotel concierge or a guest relations office on their next visit (in the case of AP). There would be several lines to get out, and a single Disney security officer could be there to assist, much like self checkout at the grocery. If used at a resort hotel, then the charge for parking could be astronomical ($100+), which again could be resolved if the charge is invalid (proof of time and date is on each receipt), and if the time of departure (charge) is within the three hours, then the fee can easily be waived or refunded as required.
Of course another system that could be used is to scan a person's license plate on exit (or entrance), much like on the express toll roads. A bill could then be sent to the car owner's home (or rental company as the case may be), unless the license plate is registered in the system as a valid guest.