I highly doubt it will be trivial. I rarely have to brake hard. But when I do, it's usuallynin an area where the other drivers are terrible and hard braking is simply more common (as are running lights and stop signs, eg Philly and parts of Jersey).

So yes, in a population of good drivers it would be simple to select people with higher rates of hard braking. But punishing them without context could lead to false punishment (similar to the cases of nurses that just happened to have higher rates of patient deaths - the prosecutor fallacy I think). Once you surpass a threshold of bad drivers in the population, it's more likely in my mind that the hard braking people may actually be the good drivers avoiding the ones running lights.