The court order is important, because it shines a light into a dark corner. Like cockroaches, bureaucrats engaged in behavior that they believe to be wrong always avoid the light.
Court involvement means court supervision and ultimately a more consistent application of justice. The courts are more trustworthy than a faceless police agency. I agree that it's a good thing that the police have access to this sort of technology -- but someone needs to watch the watchers.
Is there specific evidence in this story or any other story that you can find that the police are engaging in actual, specific behavior that is wrong? I'm not asking "are they behaving as if they're doing something wrong". I mean, has someone actually alleged harm from cell tower spying?
I ask because the police appear to be using this capability in actual investigations. They have a subject, they want to follow the subject. It's not a dragnet kind of thing.
This isn't exactly the same, but I think the issues are similar enough for discussion purposes. Police do have the ability to have investigators follow someone to learn about their behavior. But the costs associated with doing this, both in dollars and investigative resources, are high enough that police do not follow subjects 24x7 often -- certainly not to investigate some state employee's time card issues. How low does the bar go? Will the cops track me if I'm suspected of illegally obtaining fireworks? Jump a subway turnstile? Shoplift a candy bar?
This relatively new technology lowers the cost curve so much that the barrier to entry is trivally low. And that is a problem that must be moderated by some power external to the police.
Is anyone harmed? I don't know how you could argue that having the authorities systematically track someone's movements isn't harmful. Even people as irrational as crazy ex-boyfriends track the movements of their ex's to intimidate. How would you feel personally if you found a GPS tracker on your car? Or discovered that your phone was tapped? I would feel sick -- whether I was a criminal or not!
In all three of the cases you cited, you've broken a law. In one of the three cases, you broke a pretty serious law. Why am I supposed to worry that the police are collecting evidence against you if you're actually breaking the law? Who disagrees with those particular laws?
As for your last sentence, the police have needed warrants to tap your phone since the 1950s, and need a warrant to place a GPS tracker on your car, so I'm not sure what the point of those examples is either.
Court involvement means court supervision and ultimately a more consistent application of justice. The courts are more trustworthy than a faceless police agency. I agree that it's a good thing that the police have access to this sort of technology -- but someone needs to watch the watchers.