how hard do u have to get hit to get a dented pneumatic cylinder
we were hit and ended up with a dented one but there was not penalty
that kept us from continuing to the semifinals 
not hard at all, it is aluminum
and when the cylinder is extended its REALLY easy to bend the shaft too.
Pneumatic cylinders make lousy bumpers :^)
Yes, you have to design protection for those cylinders, they are quite susceptible to damage. Keep them inside or make protective covers for them.