I haven't read the whole thread, but I hope the no-helmet people are simply deciding to accept increased risk of brain injury or death, and not actually thinking that they will always be able to react to danger in time, or foresee and avoid danger by their own actions and preparations. I've had it arbitrarily proven to me that no matter how prepared, alert and foresighted you may be, your survival can still hinge on your decision to wear a helmet. And I'd hate to think of my ageing parents grieved that their son has been vegetablized or killed.