Speed of any car currently travelling on US public roads is public information, it is publicly observable, people have no expectation of privacy on this. Now imagine some technology made it possible to observe and mine this data en masse, and to issue speeding tickets all at once based on it, as often as speeding occurs. This would be so massively disruptive that the speed limits and/or the law itself would have to change to make things work back again.

This is not to have a blanket claim that law enforcement should always have less data. The point is that innovation in law enforcement tech has to be balanced with accountability, experience and changes in the actual law. Especially in a climate in which rightful use of authority is in question, the last thing we would want is to empower further asymmetry.