just been to a "classics on the common" car show in a rural very middle/upper class village - police were out, had police cadets that must have been about 13 marshalling, loads of community support guys and the odd real copper. They were being pretty laid back about people giving a bit of showmanship for the crowd. In fact, they parked a van in the center of the road at one end just to discourage people from driving like total twats and didn't bother doing much else. We did a few burnouts, made plenty of noise, had no problems at all. My friend who is a police officer was there, had to leave to go to work, just had a text saying that people have started throwing objects at the police - to be honest - I think the police did a great job of chilling out and letting everyone have a good time, its when things go a bit too far or its time to call it a night (its a residential village center) and then idiots start playing up they have to get the arse. Believe it or not, police are normal humans, I've met more than enough dickheads that aren't police to know that its not the job that makes them.