In a reenactment, how do you know when to "die" (fall on the ground and act dead)???

Answer 1

You shouldn't. That's a good way to get stepped on and hurt, or to get someone else hurt. When you die, you raise your hands and get out of the way as quickly as possible with as little disturbance to the other fighters as possible.
But there is a rules system in place for when you should leave the field. It all depends on what type of reenactment you are doing. I do medival reenactment, specifically Amtgard. Two hits to the same arm, a direct hit to the torso, a hit to two different limbs all kill. Head shots are illegal. If you are wearing armor, your attacker has to get through the armor to get to your body, then the same rules apply.

Answer 2

i think people signal you to die.

Answer 3

when you see a bear!!!!