Originally posted by rabbidrabbit 
Most all lights have flash ability with a hold on or on/off option.  The idea of the hold on is to quickly light up a dark place and be off before someone else can clearly identify the origin.   
   Try that theory out. Turn off the light in a room and wait about 10 minutes. Now do a quick flash of the beam. 

 Might as well just hold a flashbulb in front of your own face. It is you who gets the effect.
  Now get you a nerf ball or a rolled up pair of socks or something like that. Put your wife or a friend, etc in a totaly dark room. Tell them to pick a spot at random so you will not know the location. Enter the room and have them do a quick flash of the beam. See how much problem you have nailing them with the ball or socks. Absolutely none. 

  If the intruder that is in a totaly dark spot is armed and you flash a flashlight beam , etc onand off you have just painted yourself as a target.