This is like the argument about seatbelts. Many people say the current car seatbelt systems are flawed so they don't wear it for whatever their justifications. My opinion, something is better than nothing. The chance that NOT wearing it will save your life as opposed to wearing it are FAR lower.

Its the same with helmets. I'm a volunteer fireman and i have seen people do some serious damage to themselves just tripping and falling on their head. Brain damage even. Shundaroni explained what can happen best, and wyeast explained it as well. Yeah whats a $40 piece of plastic and foam really gonna do? Well any cushion is better than no cushon. Will it save you all the time? Not likely, but I would rather increase the odds than play russian roulette for no gain whatsoever.