A little off the topic, but last week I took the motorcycle safety class put on by ABATE. I had ridden mcycles 30 years ago and thought it would be an interesting class to do for the heck of it.
Anyway, they supplied all the helmets and none were vented. I rode my bike to the class and then started a discussion about why motorcycle helmets were never vented. Anybody know the answer? Nobody at the class, including instructors knew why but all though it would be a good idea for riding in the summer on hot days. Do the hoes weaken them or something? I guess if you hit your head that hard then it's game over anyway.