Received my Model S 8 months ago. Most of the time no one sits in the rear seats. About once a week on average, the kids will use the back seats and buckel themselves in. I just noticed while vacuuming the car earlier today that I've got a spot on the rear seat leather where the leather's worn through. I've never had leather wear through on any vehicle I've owned up until now. To have this happen with less than a year's light useage (that car gets driven heavy, but not much activity on the rear seats) bothers me greatly. Is this sort of thing under warranty? What should I do?