networkn: I can't strongly enough state how important I think head gear like Matt Todd wears is. It's not going to solve all issues and I understand why players don't like them, but MT is one of the premium 7's in the world and he plays fine with them on. Broken bones heal, broken brains, not so much.
There have been numerous studies which have conclusively proven that head gear has no significant effect on concussion. That headgear is good for stopping cuts and munted ears, it does nothjng to prevent concussion. The best piece of gear to prevent concussion is a well fitted mouth guard.