sainteldaily.com
OnStar plays big brother even after you have left the service
Joanne Finnor, vice president of subscriber services goes on to say that "former customers, moreover, can always disconnect their vehicle by contacting an OnStar." So even though I left something I still have to go and opt-out of the feature if they've already discontinued. So to sum it up. Even if you leave OnStar you need to call and opt out of being tracked or your data may be sold to whoever they wish.
Rubens Saintel