"It's harder to detect movement from movement than it is to detect movement from a static stationary position." I don't know who said that but I have found it to be true. If you've ever watched a fight, either a controled fight like boxing or mma or a street brawl, you may have noticed hand, body, head movement from one or both of the fighters. The skill of moving to protect yourself, hide your intent, create your opening, and mask your initiation are very important fighting concepts to consider.