There was another thread on the aesthetic of the stripe over the hexagon on the crown and I found this link on what it is for and thought folks might enjoy the read. It is a safety thing implemented by Riddell.
http://abcnews.go.com/US/riddell-unveils-football-helmet-speedflex/story?id=25141779
http://abcnews.go.com/US/riddell-unveils-football-helmet-speedflex/story?id=25141779