Once clamp load is lost, all tire loads are taken by the wheel studs resulting in a fracture of the wheel studs. This could cause the wheel to separate from the vehicle and could result in a vehicles crash without prior warning.
Paint on the wheel mounting surfaces can act as a shim between the wheel and the rotor/drum. As the vehicle is driven, the wheel imbeds into the paint, loosening the lug nut and causing a loss of clamp load.
Dealers will clean the wheel mounting surfaces for all four wheels. Also, the wheel studs will be inspected for damage and will be replaced as necessary.