What would it look like during preflight if the airframe had been significantly overloaded (aside from one wing missing or at a bad angle haha)? I recall hearing before that if the aluminum on the top of the wing is wrinkled, it is not good.
Things like flecks of paint missing, especially near rivets. Said rivets maybe loose, or demonstrating a tiny oval gap around some of their circumference.
Corrugations in the skin.
Control hinges demonstrate excessive play.
In the Cessna singles, new large areas of crazing in the front windscreen perspex, near the wing roots.
Any looseness in the struts.
Total of wings/horizontal control surfaces/tailplanes doesn't add to an even number.
Bullet holes or explosives damage.
Any large-ish dings that indicate collision with some structure, such as a hangar door frame.
Of these options I've only ever seen the last one. A ding in a leading or trailing edge that wasn't there yesterday is a good reason to have a LAME check the aircraft.