Use this trick to collect dog tags from nearly all guards. The only drawback is that it may take some time, depending on where you are in the mission; knocking out all other nearby guards before starting and targeting reporting guards last is recommended. If you cannot get close enough to a guard to demand his dog tags without being spotted, begin by tranquilizing him from a distance. Run to where he falls. Pick him up from the shoulders to make sure he is facing up. Position yourself so that you are standing in line with his head (but not literally on top of him). Also, make sure that when he stands up there is enough room in front of him that you can run around and demand his dog tags. When he starts to get up, equip you M9. The moment he reaches a standing position, hold him up. The guard will not have time to turn around and see your character. To wake up guards faster, use either the Coolant Spray technique outlined elsewhere or prop the guard against a wall (feet first, preferably), enter first person view, and punch at the highest part of his body. Both ways will get them up faster, but make sure you are in a good position to hold them up in case they wake up faster than expected. This technique also works well to salvage failed attempts (i.e. you were spotted, panicked, and tranquilized him, which is a good reason never to have your USP or Socom equipped when first holding someone up as you do not risk panicking and killing the guard by accident.)