Re: "Here I Go, Again On My Own..." - DLR
"It isn't necessary to use GPS/WiFi location data collected by a phone to track its location to within, say, a few tens or a hundred metres."
True, but at least here in North that's thoroughly illegal to do. Allowed to ISPs on court order, basically.
Of course Google/Apple wipe their asses with it knowing no-one has guts/money/legal power to sue them on it. Professional criminals by definition.