This is a very interesting topic. ANY helmet which as been in an crash should be thrown away and replaced, regardless of what the "outer shell looks like." So, to ban a type of helmet that does not show external damage when there might be hidden internal damage sounds strange to me...
I have personally been down in Arai, Icon, Shark and even Z1R and all have "protected my head" the same. Ironically... the only accident I received a concussion during was the 3rd most violent of the 4... and I was wearing and Arai Profile helmet. Go figure.