This is what can happen if you push an aircraft by the spinner - it can get stressed and will crack.
This was not detected at the DI, it was detected 1.5 hours later when refueling and had to be removed. The replacement cost was $2500 as the back-plate was cracked as well.
Do not push or lean on anyone's propeller spinner!
If the back-plate is cracked then the propeller must be removed to re-fit everything and thats a couple of hours of labour. So please do not allow people to rest their arms or push on a spinner.