As I tell anyone who starts down the tin foil path, stop and think about this for a second.
It is TRUE that you are usually registered to no less than 3 towers at any given time driving around a normal area. This then means the cell receiver is easily triangulated.
If you connect to 1 pirate tower, the pirate only has a good guess based off of the signal strength your relative distance away from that single tower point. You would need to be very unlucky and connect to many of the same pirate network towers in a single area.
But anyways, the next question would be why are you worried about this? Do you not carry a cell phone? Do you not have an internet connection? Do you never use credit cards? Do you not visit places that have security cameras, most with automatic license plate recognition? Do you avoid traffic intersections with smart cameras?
And if some criminal mastermind was tracking everyone he could, again why would you care? What makes YOU so important? If you were a high powered exec or political figure, then you have a cause for concern. If nobody knows who you are or cares who you are, then why would they care? Your car doesn't contain your bank login passwords. Is it really that menacing for a criminal to know what your current state of charge is?
If you want to disconnect it, you can either just wait 2 years for AT&T to disable all 2G com on their network or unplug the telematics unit.