The only time I suffered serious lens damage was with my OM-2 camera on the neck strap: I stepped on a huge boulder that tipped over, causing the camera to swing hard against the boulder before I realised what happened. The metal hood of the WA lens took most of the damage, but I soon found out the aperture no longer worked
The camera still worked despite the hard hit, and the lens was optically OK. As image quality was fine wide open I could still take pictures, but in the end the lens had to be exchanged for a new one. Nowadays I usually carry the camera in my hand, for a bit more direct control of where it is going in case of emergency
