Depends on the type of crash and equally how its mounted (the mount shown is both massive and pretty robust looking) - but imagine someone slipping out on a descent, whilst sliding down the road, if the camera where to hit the ground whilst sliding, it could cause the rider's head to jerk even whilst the camera was in the process of falling off, or if the rider fell directly onto it, it could cause the head and neck to pivot around it.
Depends on the type of crash and equally how its mounted (the mount shown is both massive and pretty robust looking) - but imagine someone slipping out on a descent, whilst sliding down the road, if the camera where to hit the ground whilst sliding, it could cause the rider's head to jerk even whilst the camera was in the process of falling off, or if the rider fell directly onto it, it could cause the head and neck to pivot around it.