I confess to often exceeding the speed limit, particularly on motorways and dual carriageways (but never near schools during or near school hours), but not by much, only when I perceive it as safe to do so, and at worst generally within the ACPO guidance. I see little risk in doing 155 mph in a roadworthy E55K on a bone-dry, deserted motorway in daylight, but I would never do it; firstly I'm chicken, and secondly it's too risky - I need my licence.
Police traffic patrols, which are so few on the roads these days that the risk of being caught by one is pretty slight anyway, will I suspect have no interest at all in issuing tickets for 71 mph speeders; they have better things to do. What worries me is the cameras; they have no discretion to exercise.
The problem is not speed per se, but inappropriate speed - driver behaviour, in other words. This whole thing smacks of nothing but a politically-inspired soundbite measure. "We want to impress the public with our concern for road safety; it can't cost much, because we can't afford much, but we have to do something; that's something, and it sounds good, so let's do it."
Scotland today, the rest of the UK in due course? We the driving public can't stop it, but let's just wait and see what actually happens...