The problem is that to be useful for law enforcement, any local police department has to be able to go to any local judge and get a warrant and then get access.
There are approximately 30,000 state judges with fairly high turnover in that list. If you can compromise one, or successfully get yourself added to that list, you can then get access to whatever you want. That's way too many people to trust.
This is not a hypothetical weakness. I personally know someone whose physical location was compromised through a court order obtained by bribing a judge. How many cases are there where similar access was gained but the victim doesn't know how it happened? And the better the access that you can get, the more incentive there is to get it. (There is no shortage of reasons why a motivated party would want such access.)
The problem is that to be useful for law enforcement, any local police department has to be able to go to any local judge and get a warrant and then get access.
There are approximately 30,000 state judges with fairly high turnover in that list. If you can compromise one, or successfully get yourself added to that list, you can then get access to whatever you want. That's way too many people to trust.
This is not a hypothetical weakness. I personally know someone whose physical location was compromised through a court order obtained by bribing a judge. How many cases are there where similar access was gained but the victim doesn't know how it happened? And the better the access that you can get, the more incentive there is to get it. (There is no shortage of reasons why a motivated party would want such access.)