Firstly, the entire port of insurance is to spread risk. If the the market for insurance is "too efficient" at determining who is high-risk and who is not, then it is no longer fulfilling its social function.
Secondly, you seem to be implying that only aggressive drivers are getting flagged by the data. But the computer doesn't know if you accelerate and brake hard because you're an aggressive driver, or if your circumstances require it. Maybe you have to commute to your job in heavy stop-and-go traffic with difficult merges.
Finally, this kind of surveillance changes behavior in ways that may make things less safe. If you're driving down a street and a ball bounces out from behind a parked car do you slam on your brakes out of fear that there is a child chasing after it, or do you think that hitting the brakes might make your premiums go up so you just hope that there isn't a child coming.
Secondly, you seem to be implying that only aggressive drivers are getting flagged by the data. But the computer doesn't know if you accelerate and brake hard because you're an aggressive driver, or if your circumstances require it. Maybe you have to commute to your job in heavy stop-and-go traffic with difficult merges.
Finally, this kind of surveillance changes behavior in ways that may make things less safe. If you're driving down a street and a ball bounces out from behind a parked car do you slam on your brakes out of fear that there is a child chasing after it, or do you think that hitting the brakes might make your premiums go up so you just hope that there isn't a child coming.