I let a friend get in the driver's seat to drive the car, and they didn't disengage the parking brake and just started accelerating. They only made it a few feet from the driveway before I caught the mistake. I realize a few feet with the parking brake on is no big deal, but more out of curiosity how bad is it if the parking brake is firmly engaged and someone drives for a bit. Say 1 mile, or 5 miles, before noticing?