It's not necessarily the pilot that over-torques the props. I lightly torque the props onto the motor drive shaft and invariably, at the end of flight, find them much more tightly screwed on - particularly after a turbulent flight.
No big mystery - the angular momentum of the motor is constantly working against the prop's resistance to rotate in air, causing the prop to be torqued tighter on the shaft.
Angular momentum really comes into play when a prop slams into a fixed object and STOPS, as in a crash. That's when the motor's momentum augers the drive shaft INTO the prop and you go find a pipe wrench to twist the motor out of the fused on prop.