It's a safe assumption. Trust me. Factor in the complete unconsciousness for 30+ minutes, the semi-consciousness after that, the massive facial injuries and the impact the helmet absorbed and figure it out. Let's put it this way: I don't want to find out.

Why are you so hellbent on convincing people that wearing a 9 oz helmet (that is so light I've gone out without it on and not realized it) is a bad idea? Are you completely nuts, or do you just have it in for all bike weenies (not that anyone could blame you)?