Many (most?) cars ship from the manufacturer with overinflated tires. I have read that it is done to help prevent flat spotting the tires when parked for an extended time during transport. Especially when strapped down on a ship/train/truck, the tension on the straps significantly increases the static load on the tires. When a new car is delivered to a dealer, setting the tires to the proper inflation is supposed to be part of the "pre-delivery check".

I have noticed that a significant number of the rental cars I have driven were overinflated, and just assumed that they didn't check it.