I always have to laugh when I see the squids. I'll bet they think they're really cool...right up until they biff it and turn part of their body into hamburger, or worse if they also passed on the helmet. Even when it's hot out, I'll wear my gear. Lots more painful if you don't, and you dump it.

Someone riding like Rondog described won't make it too long without having an "unintended consequence".