People drive rentals like a rock star takes care of his hotel room. Buy a rental at your own peril.
While surely in some instances, it's largely a myth.
People often rent cars in unfamiliar areas, and tend to drive slower because they don't know the terrain. You don't want an accident or trouble with the law.
Last summer, I rented a car in Saratoga. Cops are very vigilant up there. I literally didn't go a mile over any speed limit.