This is true, but if you follow someone consistently enough then it is considered a crime--stalking.
Exemptions for special cases (PIs, bail bondsmen) were put in place with the expectation that those groups would not abuse the system, being "professionals." And of course the police have been allowed to track people under investigation. But private individuals and businesses do not have the right to stalk people.
It's time to put to rest this notion that occasional incidental observation of other people has anything in common with the persistent surveillance enabled by modern tech. One is expected and is fairly low risk, the other is ripe for abuse.
If we use electronic devices at all, we're just best advised to operate as if the government has access to anything we say, write, or record on them. That includes our locations. If you're going to see your weed man, or your mistress, you probably want to leave it at home. And no, don't bother buying a "burner" because they can track that too.
All that said, companies should try to keep your location information secret from anyone other than the government. One of the issues right now is that they don't. They make good money using location to target ads for instance.
It's not like this requirement was an inevitable outcome of governments. We can change laws.
Taking your phone or your DNA to any such tryst makes it so apparently.
What's worse, there will likely be a lot of scope creep. It's showing up in criminal court. It's showing up in civil court cases. It's definitely going to be showing up in family court. Etc etc etc.
it's a bummer for sure, but it's been this way for a while. it's perfectly legal for your wife to hire a PI to follow you around. the police also don't need a warrant to observe your movements.
the part that's new is that all this surveillance can be done passively without any particular reason to suspect you.
imo, the distinction between public and private spaces is pretty reasonable for targeted investigations and observation by fellow citizens. in my view, the real problem is how long information should be stored, especially when collected passively.