There, fixed that for ya. Amazing how they managed to get darned near 100% of the population to agree to carry around a tracking device with nary a peep. All it took was to be very careful to NOT talk about the tracking ability, keep news accounts of the police using the cell data off the front page and make the tracker shiny and useful enough. Do those things and not only will everyone carry one they will pay an average of $50/mo for the privledge. Land of the Free indeed.
Won't be long now before they decide they have the hook set deep enough they can start making more overt use of the location/activity data without many people ditching their tracker.
The carriers WILL start renting out access to track data for advertising purposes. They know where and when you are. They will be able to link that beyond your phone. Won't take much computation to get that localized enough to have a good idea which PC you use and then tie it to doubleclick and google's cookies. Then they know EVERYTHING. Combine a tracking cookie to hard billing quality identification data and the possibilities are truly limitless. Sure they COULD do that with Amazon but there is too great a chance of a user revolt. But people won't/can't give up their iShiny.
What law enforcement will do with the data is so obvious and so dark there isn't much point in hammering it again really. Especially combined with security cameras everywhere. Who cares if the image quality isn't good enough for a positive id or you were wearing a hoodie. It gives a time/location and the tracker gives them who was at that spot in spacetime.
Bust a drug dealer and you have probable cause to grab a trace on everyone who came in contact with that person for the last month. Crunch the numbers enough and lots of patterns emerge. Not quite precrime but close enough. You show up as having been in the room with a number of dealers and that will be your ass. Or be around a few people who later get busted for burgulary and how soon until that is cause for a search warrant on your place? Being able to effortlessly work backwards from a bust and turn up clues like that will change the law enforcement game entirely.
And now you see why AT&T yanked all their payphones and for some reason simply refuses to compete in the landline business, even with billions and billions in sunk costs for all that wire going everywhere. Eliminate hardlines and everyone MUST buy a cell. It is already sorta odd to encounter someone who doesn't carry one, eventually it will be reasonable suspicion of criminal activity. Wouldn't suprise me if they become the preferred physical identifier, i.e. 'your papers.'