So if for instance I were followed by a police car, and they clocked me exceeding the posted limit (and bearing in mind that a traffic officer is regarded as an expert in this field in in a court of law), they pulled me over and charged me for speeding, that is not the same offence as undue care and attention, or the greater charge of dangerous driving.
If they were to want to take it through the courts, and raise the charge to one of dangerous driving, then they would have to present evidence to that effect.
The notion that anybody exceeding the posted limit is automatically guilty of dangerous driving doesn't really hold water, and an uninformed opinion carries no real weight when put to the test.
I don't think Ben B is making that point. He seems to me to be suggesting that by imposing a speed limit for a section of carriageway, the authoities are implying that any vehicle exceeding that speed without any legal reason to do so is driving at a speed beyond that which is considered safe for the road in question.
One might conclude that the driver is therefore taking risks above and beyond those considered acceptable under law or (by implication) driving in a way which is not safe.
The offence of Dangerous Driving is another kettle of fish altogether and not, I think, what BenB is referring to.
It seems perfectly reasonable to me that the authorities in a democratic society should introduce a system whereby vehicles passing a given point at greater than a legally imposed and clearly posted speed limit should be subject to a fine and/or further punishment.
In the 'good old days' I benefitted from several 'Gypsy's warnings' from well-meaning traffic officers and then went off to do the same silly thing again. How much fairer to have a system that simply results in my being reported for the offence of speeding every time I trigger a device.