I never enabled the 'tracking' in my myChevrolet app/website (it's called smart driver). I ensured that it was off when I bought the car. The dealer was going bananas trying to get me to create a myChevrolet account. Now it makes perfect sense why, they must be getting a kickback as well.
Anyway, some scare mongers said that they track & sell the info even if you have smart driver turned off. So, I proceeded to request my LexisNexis data and indeed there is nothing related to my driving habits in it so at least for now, GM respects the Smart Driver choice of the consumer. There's no guarantee of course that they will do so in the future. This needs a good smack down. Some US states provide protection against this kind of stuff. My state (CT) does, so I am proceeding with using their mechanism to ensure that I am not tracked without my consent.