We're a soft target. Remember back at school. Now tell me, did the class bully pick on the big guy with lots of friends, or the small quiet kid with less friends?
It is much easier to convict and charge non-criminals than it is to do the same with hardened thugs who don't mind beating up someone's granny to steal £5.
A colleague of mine received a ticket through the post at the weekend: 52mph in a 40 limit. Now, this road used to be a 70mph dual carriageway, but someone decided to lower it to 60, then 50, and recently 40. It is easily suitable for driving at 70, and lowering it all the way to 40 is just stupid. There is very little traffic on it, there is no reason to walk on it as there is nothing around except for a pedestrian footbridge (and as he found out, a camera van)!!! However, he just grumbles "Fair cop I suppose" and is paying the £60 fine and taking the 3 points, because there is no point in arguing with a posted speed limit no matter how silly it is.
If anyone is taking a trip to Hampton Court and goes via the M3, you will be driving on the A308. The two miles up to Hampton Court have been reduced to a 20mph zone. Nice wide road, perfectly safe at 40, now a 20. I almost always drive at the speed limit everywhere because I don't want to get points, but because I drive at 20mph on this road it is very dangerous. Everyone wants to overtake and generally does it very badly. Also it is a danger for cyclists as they will find themselves travelling as fast as the cars and thus are unlikely to be seen if they happen to be in a blindspot as they will remain there.