I have wild camped all over the place and never once been asked to move on, that is not to say that I will never be. I suspect that local authorities are scared of encouraging Travellers to park up due to the legal cost of removal. My method is simple, Only park up for one night and move on. If it is at all possible, I ask permission, and the normal response is "as long as you are not looking to set up camp".
Wild should really be Widerness as that is what it is about. I dont want to park up in the middle of a city, I want the peace and quiet of the country side. I have stayed on many a car-park with the feared "no camping" sign, have had the Police circle in the middle of thew night, and go on thier way.
I dare say they come back later to see if I am still there, but as I have said, only one night, so I am gone. Never been moved.
Use common sense, keep it clean and clear. and you shouldnt have problems. with exception of yobo,s. But touch wood, I havent had problems with them.