@Gnasher Re: @Buzzwords Symbiotic relationship
So, you say :
"That's not how it works. Most likely, location services will just turn on GPS, which cannot be tracked."
I suggest you learn a little bit more about how GPS works and how location services works.
And its AGPS or assisted GPS which uses land based Wi-Fi to help identify your position if you're not able to get enough GPS sat signals to locate your position accurately enough. Note: If you don't want anyone to use your SSID to identify your location, you just don't broadcast it. ;-)
The point is that if location services is on and is always on, the app will wake up periodically and get the GPS location. (I would suspect that its not the GPS location but the AGPS location provided to the app by an Apple API call. Just if you want to get technical about it...) Then transmit that back to Uber. The GPS data and the unique identifier of the phone is enough to track you. The could use the app id too, but why bother since they want to know the actual phone which they do track.
And if you want to get technical, the mobile phone company which operates the network automatically can track you based on where your phone is and is on. (Its always connected to a cell tower and because of that it can give your location to an approximate location just on that alone. ) I won't bore you with the details but within a city, your location within a .1 mile radius would be the norm, in the countryside, it would be a larger radius. Also as towers hand off your phone to the next cell tower in the network, they can track your path and give you a slightly more accurate picture of where you are.