Adrian
When you see a flashing road sign, you slow down and start to revert to form the next day or whatever. If you get a £60 fine and 3 points on your licence, you are going to be a lot more careful.
Getting caught speeding is the act of someone who is either taking a chance or just a bit dim. Either way it is a good thing to get them off the road which means less conjestion for the rest of us.
The simple answer is don't break the limit and you won't get done.