Originally Posted by
Yourface
Except shaco's dont put their boxes all around the map, they put them all in one spot.
Through controlling one point with insta-death, you cause all points on the map to be at least cautiously concerned about. It's not necessarily about being everywhere, so much as letting everybody know that if you are unfortunate enough to stumble across it that you're boned. Jungles get massively paranoid about it, and roamers tend to play it safer after the first time.
It's map control through fear, not map control through sight, when that occurs.