Loss of Safety factor
The 1.5 safety factor is also generally applied to military aircraft.
One popular light attack jet had wing tip lights fastened by 6 screws, 3 on top of the wing, and 3 on the bottom of the wing.
Aircrews and maintenance workers did not generally understand that flying with one screw missing then provided NO safety factor for that particular piece of equipment. Aircraft would often lose these lights on flights where the maximum allowed g was being approached.