I had heard something similar to this before, but I don't buy the statement that helmets do more harm than good. I think the issue is with some of the "aerodynamic" shaped helmets that have parts that can "catch" on the pavement in a crash as opposed to a more round helmet that wouldn't do that. If the helmet catches on the ground I can see where it would cause extra rotation. I think it was somewhere on www.helmets.org that recommended looking for a helmet with a very rounded shape to avoid this issue. As for helmets discouraging people from riding, I don't buy that either. Especially with as lightweight as helmets are now (my first helmet as a kid was one of those hard-shell Jammer ones that weren't all that well ventilated either, and things have improved a lot since then!). I think I'd be nervous riding without mine.