Yeah, but if they dont issue a fixed penalty notice, then it like saying "your fine to do 40 in a 30 mate". It sets the precident.
On two sepearate occasions, in two different locations, I have had near-accidents where I have been doing ~30mph and a kid has run out into the road without looking, and if i had been doing 35mph, I would have hit the kid, but because I was doing the speed limit, I stopeed with only a metre or so to spare.
The speed limit has clearly prevented those accidents, and to me, that is more then enough justification for anyone doing over 32/33mph to be rewarded with a fixed penalty notice.
Drivers who drive at around the 40 mark in 30 limits, even if its only 37/38, no very well what they are doing, and they are well aware of the risk they are taking, not only with regards to police but also from a saftey standpoint.