Some rental car company will let you drive on bald tires or under 2/32nds of treadlife left. You point it out, they tell you go do a tire rotation and they will pay for it. Might as well get another car at that point. They dont really inspect the vehicles much for the next driver. They just wash the vehicle and thats it.It would be the common courtesy to call the agency and tell them so they can make the decision. Just like calling them if something is not right on the car. I had to do that once with brakes. The agency (Hertz) quickly got me another car.