This appears to be a growing problem. Friends told me about a worrying evening at W***** recently, where a 4x4 and 2 vans turned up, men piled out & started hauling people out of the woods.
Another post on here referred to a Facebook page used by people who organize forays to dogging sites to cause trouble. Given the nature of the internet, the phenomenon seems to be spreading, with these self-appointed ' protectors of public safety ' cropping up more widely. I've been mentioning this to some of the folks I meet so they are aware of the possibility & can be careful.
Wrt the Facebook page, I informed a mate who has contacts in the police. He made enquiries and they are onto the page. He was told by his sources that they ( the police ) aren't so much bothered by the cruising / dogging that goes on, but they are bothered about those causing trouble.
Of course, the whole business is pretty loathsome. Things are certainly pear-shaped when people who want to have harmless fun are targeted by others who plainly have some sort of mental disorder, or at the very least are getting no sex themselves and can't therefore bear to see others having it.