No comment on the helmet, helping / not helping. However I can say that all my bad crashes / skis, Bike, Street bike always seem to come during that (Last time down, around) You know you have pushed it!. You feel that you are worn down and no longer 100%, You have a bad vibe and your thinking last run, And BAM the inevitable explosion. Yard sale on skis, jacted up knee, split head. Severe road rash totaled bike and on the way to the ER.
Seems for me its always like that>?