> I understand my current carrier can potentially deduce things about my habits in the unlikely event that they were so inclined

I worked for one carrier and part of our project was exporting (without names) location history to some external company which then provided segmentation into categories like "student", "stay at home", "working", "retired" based on how people move. The results were then reintegrated and used for marketing purposes.

So they absolutely can and they absolutely do that.