Residential streets.
The thing for me that makes speed cameras a load of old haddock is that there aren't ANY on normal residential streets, you know the ones, where your kids live, old people, pets, normal people, etc. Every street I've ever lived in, people hoon up and down them, often past small schools and day-care centres, not a speed camera in sight. The little street where I work, people ping up there at 40 and 50 all de day long.
but of course, get out onto a country road where there's feck-all danger of hitting anything other than a rabbit, (A34 anyone?), and all of a sudden it's imperative you do 30 or you're nicked me' old beauty. It's utter balls. It's not about safety, it absolutely can't be when you look at their choice of placement and distribution in any given town. Follow the money...
So here's a question, if you can prove that you were somewhere else when the camera got your plate, (i.e. you're claiming someone must have cloned yours), do you get away with it? If so, let's start up www.speedingalibi.com whereby lots of people in the UK register and stand testimony once a year for some random other dude somewhere else in the country saying something like: "Mr Davies? Speeding in Renfrewshire on Saturday? Couldn't have been, he was with me watching the cricket!" Or somesuch. Or go one further and use CCTV in your home, at your work, shop, blah on any given day, change the date (which is often configurable), hey presto, alibi!
Failing that, how about clear but smokey stickers that go over the lenses of the cameras. They'd take a sec to put in place, be unnoticeable until used and would fuck up any image making them useless. I've often thought about this, do your community a service and get a broom-stick with a little sucker on the end of it, get a clear but foggy sticker of roughly the same proportions as the camera lens and as you walk past the camera, quickly splodge it on. Job jobbed. I'll do my local ones if you want and you do yours. Come on chaps, Battle of Britain Spirit and all that!