Flying Lawyer, a couple of points :
You are quite right to say that there have been fatalities with Police road vehicles being involved in accidents. Unfortunately, some of these have involved nothing more than chasing "joyriders" in stolen cars. How do we define when it is and when it is not safe for a Police driver to break the law? In fact, do Police drivers have exemptions to the Highway Code / RT laws?
As you also state, the majority of Air Support pilots are ex-mil. As a result, they are very mission-orientated. They have also flown in a lot of situations that in civvy life would be either illegal or just plain dangerous (single-engined through / over the clouds, cloud breaks in a Gazelle equipped with nothing more than a Zip lighter and a BBC2 aerial, that sort of stuff) So, if the observer says "lets go look at that over there" (there being a completely built-up area with nowhere to go in the event of a problem) the natural response is going to be to go and do it - because that is todays task. The problem I see is that the flying is undertaken as some sort of quasi-military operation - when they are subject to civvy rules and regs (with certain exemptions)
And related to that you say "Why not credit them with some ability to make a sensible judgment about what is, or is not, a justified risk in any given circumstances?"
Well...not really.
Firstly, risk taking and helicopter flying don't go together. Secondly, The PAOC lays down the rules about what they can and can't do whilst flying air ops. It is not up to the pilot to arbitrarily decide that today he will hover over a built-up area at MAUW with no emergency landing area available. If he does, and he comes unstuck, then he should have to face the music. And if it was your house he landed on, would you still feel the same?
TC - I hear what you are saying about the size of built-up areas. I'm not saying don't fly over them. My point all along has been that any helicopter -police or civvy has to fly with a view to landing clear at all times. If Police Ops conflict with this, then either the rules or the ops should be changed.
As for the Americans, when I was over there it seemed there were Squirrels going down on every street corner (just avoiding the schools, of course). Yes, singles are accepted by the FAA and the public. But whereas in the UK we citizens may be at danger from the odd speeding joyrider or shoplifter, the citizens of LA have to deal with the possibility of coming face to face with a gun-toting crack-crazed lunatic on a daily basis. So I can see they may be more understanding of a helicopter crashing whilst patrolling their streets. Do we really have the heavy-duty crimes to justify it in the UK? I think not. If we did, the skies would be full of newscopters too. Even G-OITN was mothballed due to having no juicy stories to film.