The signs say no overnighting, and whether it's enforceable or not (apparently not - for now....) I agree 100% with maingate about idiots with campers thinking they can just ignore the notices and do what they want.
Alnmouth is a honeypot because it is such a pretty Northumberland coastal village, but if you start getting increased numbers of covidiots basically sticking two fingers up at parking signage then, tbh, I can't say I blame the Burbage Holders from wanting to stop them from abusing the site.
And by abusing, I don't mean leaving rubbish or behaving badly, I mean taking liberties in what is a fairly high-profile tourist car park managed in conjunction with a burgage system. I say if you invade in campers and proceed to show your monkey bums to the natives' parking signs then you should fully expect a smacking in return.
As for parking safely on the roadway elsewhere in the vicinity then fair enough, but it is a small place not suitable for accommodating masses of vehicles in or around the main village, whatever the size of the vehicles. Hence the need for the beach car park.