I've done both, had I found the answer I wouldn't have registered for an account. Since you seem convinced this has been answered elsewhere, and I must have missed it, I'd appreciate if you could point me in the direction or just answer my question.
The car limit was previously 4 for camping, per camping ticket. Now each ticket is all inclusive, meaning everyone is paying for camping with their festival pass. Fill your car/truck/RV with as many people as there are tickets to the festival.