I don't agree. As you are aware, any 'profit' that the camera partnerships make is ring-fenced to be used for additional cameras or other road-safety initiatives. By all accounts they seem to have plenty of money rolling in! Paradoxically, it is my view that the flow of funding from errant motorists would dry up if cameras were used more effectively. What is the greatest deterrent? - The fear of being caught and punished. Why do drivers still speed? - Because they know there is a far greater chance of them getting away with it than being caught. If the number of cameras was dramatically increased - and hidden - then there would be an initial big increase in the number of prosecutions but then, as drivers began to realise that the chances of them being caught were far greater than the chances of them getting away with it - their behaviour would change and they would begin to remain within prosecutable limits. Hence the number of drivers being financially penalised would decrease significantly. In a way, painting cameras bright yellow is not doing the speeding motorist any favours because it is lulling him into a false sense of security about his actions!
Kev