O95,
Do you have a cellphone? They already can know where you are even when you're not using the phone itself. My neighbor is a homocide dectective for a metro Atlanta police jurisdiction and a couple of years ago there was a pretty bad murder case where the perp fled the State. He was later captured several States away and was done so by using his cellphone to triangulate his exact position. Your cellphone in order to maintain contact with the network is always sending out a signal to the area towers in order to post those little bars at the top of your screen.
Don't want them to know where you are? Either don't have a cellphone in the first place or take the battery completely out of your cell and then you might be safe. The overwhelming vast majority of us are extremely easy to find even without On Star via our cellphone.
Do you live in an area with lots of highway cameras? If you do it may be possible on some routes to literally follow a person to a destination if the cameras are all along the route. My wife couldn't believe that the cameras are accessible to anyone on the net and I had her online and with me on the cell while I rode by one camera and waved at her in real time. And these systems are getting bigger and bigger and our local gov't has had meetings on installing these more and more and using a traffic cops in order to place police to meet other needs and to reduce police manning and thus cost to taxpayers. Also the cameras are lower cost to maintain so the fines derived from these cameras over the longhaul would provide a larger profit margin than the current system as well as more and more people would forego court and just pay the fine again lowering costs and increasing profit margins to the county gov't. I attended these meetings as they were public and the term "profit margin" was the county officials words not mine. Also they could use Homeland Security funds to install the cameras and to the public sell the idea as Homeland Security protection but the real goal it local law enforcement specifically traffic enforcement.
We generally get up the same time everyday, leave home the same time, drive to and from work the same route, weekends are generally the same and pull up your economic activities over the past year. For the most part, the majority of people do the very same thing over and over and over again. We are truly creatures of habit and therefore easy prey if someone wanted to track you.
If you only knew what the later model package cars with it's onboard computer could tell about you! Especially when it's piggybacked with GoggleEarth! That's when you'd really freak out!
I've seen you out there!!!!!!!!!!!!!!!