I went over this like, 2 posts ago.
hahah, because something hurts or not is a great way to judge the amount of energy transferred to your brain. I've hit my head on lots of stuff in the plane, including being a rookie and taking the door to the head. Would it have hurt a lot without a G3 on, obviously. Am I stupid enough to think that if that blow was hard enough to give me a concussion the helmet would do anything significant to lesson that blow? Absolutely not. I'm not saying it is zero, obviously the shell deflecting and the liner mushing will absorb some energy. I am saying that instead of a concussion its lowered to a headache, or instead of a TBI it is lowered to a concussion. That difference is critically important. But sure, the G3 might make sure you have a pretty face while you suffer from PCS, or recover from a TBI.