Re: @Buzzwords Symbiotic relationship
"On my iPhone, I don't turn on location services because the ToS has it set to either be off or always on.
Which means Uber can track you even if you're not using the app."
That's not how it works. Most likely, location services will just turn on GPS, which cannot be tracked. Your device might instead use phone towers or WiFi routers to determine its location, in the last case some Apple server will be asked if it knows the location of one router, this is supposedly anonymous, and it returns locations of all routers in some area, so if you walk around in your village your phone knows where all the routers are and doesn't ask Apple again.
So if you believe Apple, then nobody can track you. If Apple is lying, then Apple can track you. In no case can Uber track you when you are not using an Uber app.
And what Uber actually did was finding out whether you had uninstalled their app and installed it again, because apparently you could get a $20 voucher by doing this. Which they shouldn't be able to do (whatever method they used, you'd hope that Apple stopped it from working). And it's stupid, because if you buy a new phone and sell your old one, the buyer of your phone couldn't use Uber.