Western NY AAA policy is they only give them if you book a trip at Disney or a Neighbor hotel. They used to give them with park ticket purchase. Thier brochure still states this. I am "discussing" this with them now. My understanding is the AAA Diamond Parking Pass polciy varies from AAA to AAA.
That being said, it doesn't make a whole lot of sense, if your staying on property you don't really need a parking pass since you will most likely use WDW Trasprotation (yes I know you still may opt to drive) But if your off property you HAVE to drive so the AAA diamond parking is a perk. BTW we just bought 20, 5day PHP NX.