User blog comment:GossipQueen/Twisted Challenge/@comment-1874924-20120218222256

The video reminded me of something I once heard in a safety/security presentation: unless the attacker telegraphs the attack in some way, it's physically impossible for any human to defend against an attack from two feet away, because the biochemical processes that operate our reflexes are too slow. A three-foot distance provides enough warning for a few people, and a four-foot distance provides enough warning for most people.