Some people take an astonishing amount of Stuffs to festivals, which they then drag from the car park with some difficulty. They often have little carts for the purpose. Or, even more amusingly, wheely suitcases. Hence they ‘need’ their cars.
For our last festival, it was far preferable to get a coach with backpacks; the coaches had access to roads that the cars did not and there was no queuing. There was quite a jovial atmosphere on the coach, too. We had a great time telling this to the people who were complaining about queuing for ages and then having to drag their stuff miles from the car park. Not that we were smug, or anything…
I feel sorry for them about the mud, mind. Camping in that must be miserable.