I liked that article. Its funny how grappling and basic self defense can be used by anyone.
I believe there was a blind person who entered at the Senior Worlds one year I forget what belt. He can't see the person during the roll but goes by feel. Incredible.
My classmate who returned to live on the Big Island of Hawaii and trains with BJ Penn also closes his eyes when he rolls and goes by feel, he can see perfectly but prefers to close his eyes when he rolls.
I was an assistant coach in Dover, DE and we had a blind kid on the team. After wrestling with him.....I have no doubts that he could mess somebody up if needed. Once he gets ahold of you, sight doesn't mean too much.