Go bags are for when S*** hits the fan in real life and you need a way portable survival kit which will allow you to live for several days. Whether you are waiting for rescue, trying to make your way back to civilization, or maybe if you just forget to pack extra food and don't feel like driving all the way back to town to buy more.
*note this doesn't have to be strictly real world if you have a go bag you use when you play airsoft that can be posted as well.
Anywho I'm curious to see what your guy's kit includes and what bag it is in.
Personally I have mine inside of a camelbak mule and it includes the following:
pocket knife with serrated edge
a mirror (small and flexible)
small tin of tinder
1l of bottled water
empty hydration bladder with hose
strips of toilet paper
extra cellphone battery charged
+plus some other less exciting items