There is nothing in the GR about having to walk into the AZ. Where the available parking is within the AZ some purists hike out of the AZ and back to set up, but this is not required in the GR. Indeed, we have summits in the UK where the size of the AZ is measured in square miles and the AZ contains towns. All that is necessary to be within the rules is to remove your gear from the car and carry it a reasonable distance to a suitable operating position where it will not cause problems for other summit visitors. Easy access summits are very much in the minority worldwide, as I said above, they are useful to let the less mobile operators get a taste of SOTA, but I imagine that nobody is going to achieve Mountain Goat status on easy access summits!
Brian