Cars learn a lot from their owners. They know about their location. Where they're parked at night. What routes they usually take to work. What doctor's offices they visit. What churches they attend.
They know about their driving habits: how often they brake hard; how loud they set the volume; when and where they drive faster than the speed limit.
As they've added new connections to cars, automakers have increasingly harvested and stored such information to establish new revenue streams, using it for advertising purposes or selling it to third parties.