In reply to Adam Moroz:
People dossing in the woods are generally fine, as long as they behave and don't start showering/pooing in the campsite bar without paying or even buying a coffee (unfortunately quite common).
The biggest problem is the hoards of camper vans clogging up every car-park and layby on every holiday weekend. The problem has definitely got worse in the 6 years I've been going there regularly - ali k's description in the thread you link to is accurate. I wouldn't be surprised (or, in fact, disappointed) if the local authority will start to introduce restrictions.
This said, if you're just going to bugger off into the woods with a bivvy bag you should be fine, as long as you use your loaf. Go a fair way from other people, don't make too much noise, don't light a fire (this is a very big no-no), bag or bury your poo, respect the environment etc. etc.