I covered much of this in a few posts in the other DVC thread on this topic. For those who believe Disney may be doing us some favor by not charging us for parking while charging regular guests that reserve through Disney, it is not a favor. I have seen situations like this before in which the internal "suits," who often care little about the impact on customers, come up with another way to make money by charging fees to customers including owners of condominiums or timeshares. The usual internal process for something like this is the "suits" go to the lawyers and say we are going to charge fees (such as parking), and they usually have every intent of charging everyone including owners unless the lawyers say they can't. I am also guessing the lawyers in this situation said no, you cannot charge fees for DVC members use of the parking lot of a DVC resort.
The parking lots are common elements. The owners, and anyone to whom they rent or give (such as relatives) reservations have a right to use the common elements both under the law and under the declarations for the resorts. Moreover, such right, as a matter of law, is automatically included in any resale contract and thus you cannot distinguish between original and resale owners. No fees can legally be charged for use of any common elements absent such fees being spelled out in the original declarations or added by majority vote.
Of note here also is that the Disney entity that is actually setting and collecting parking lot fees is not DVD, the Association, or the managing entity (DVCMC) appointed by the association to run the DVC resorts. It is instead the Disney resort entity that has ownership of all the resorts except DVC, which cannot charge members for use of the common elements for the additional reason that entity has no real ownership interest in the common elements of the property except to the extent such interest is retained by the hotel part of the property.
However, that entity can likely charge for parking to resort guests who rent from Disney -- the charge is simply considered part of the rental fee applicable to the room and that guest's use of the resort. DVD retains a small ownership interest in each DVC unit, which interest includes its right to rent that interest and use the parking lots. Moreover, when owners trade out, DVD gets all the rights that owner has in the use of the unit and common elements of the resort; the same applies to when DVD gets the right to rent rooms at and after the 60-day breakage period from time of arrival. In those situations, DVD can likely charge a rental fee for parking to the guests to whom it rents, and such parking fees will not be considered amounts that need to apply to offset dues, except to the extent that it must first apply income from breakage period rentals to offset a small percentage of annual dues of the resort. However, the parking fees will likely add nothing to offset dues since annually the required amount used to offset dues has, in the past, been met for each resort just out of rents for the rooms themselves.
If Disney tries to charge parking fees to members, renters from members, or relatives or friends of members to whom a member gives a reservation, everyone should consider it wrong even if you never bring a car. My understanding is that for parking fees in California and Hawaii, there is no charge for anyone having a DVC reservation (even if not a member). Likely the same is happening in WDW. If Disney were allowed to get away with charging members, or guests of the members, for parking at the resorts, that would be the same as conceding Disney can charge any user fees it wants for use of the common elements. We could soon see charges for use of the pools, playgrounds, walkways, lobby, hallways, or just generally for the "use of common elements." Your common element use fees bill for a trip could easily excede your annual dues.