Some time last year I wrote a comment here on HN about my Bolt EUV and OnStar. I can’t remember exactly what I wrote and don’t want to dig for it, but I said something like being happy with the vehicle and had disabled all of the OnStar features/tracking soon after I purchased it. Somebody replied that they were intimately familiar with the OnStar/GM project, having worked on it, and that it was still tracking me despite not being subscribed to any of their services and having turned off all the features in the car that I could. They couldn’t elaborate further, I assume because of an NDA or something. I bet dollars to donuts that this is what they were talking about now.
Edit: thanks to Stavros for finding the comment below. It looks like you were in fact the person I was talking to 11 months ago. Small world!