This sort of mass tracking shouldn't exist and it certainly should be illegal to sell this data. Anyone who is capable of tracking (e.g. satellite companies, cell companies, etc...) should be required to immediately report any request to access this sort of data. If it's a government, force them to publicly give reason and use that to scope the investigation. Our technology makes this possible, our culture doesn't have to.
I don't see how publicly won't fly. If for the sake of an investigation, they need discretion, that should have a reveal time or reveal condition that is not too broad. For example, "When the investigation is complete or two years, whichever is shorter." Then match up requests (including rational in the form) and responses. Requests outside that are illegal.
Sure, I could go with two years. Even that's probably too long. But publicly announcing the tracking requests at the time they start? Announce to the suspect that they're being tracked? That's a bit of an unreasonable handicap to an investigation.
A warrant is not an unreasonable handicap. No warrant? No data. If you don't need the data bad enough to get a warrant, you don't need the data bad enough to get it.
