Towersey have everyone who wants to drop stuff off on the campsite queue up in one of the fields that will later be used as a carpark, issue them with numbered "unloading" tickets and the stewards using walkie talkies to keep in touch with those at the camping gate regulate the rate at which they let them go. Only those with an unloading ticket (and their fest ticket or receipt) get let in, people without the ticket to show they queued up are directed to the field to the back of the queue to wait their turn. It does take a while for everyone to filter through but at least it's fair and it reduces the congestion. Those hardy souls who can carry eveything on their back don't need to queue and so get in quicker.