People who abuse the VOIP.
Instead of: "They're in the left stairwell"
They say: "Yea, well I was walking along and I seen them on the left hand side, in the stairwell. I took a couple of shots at them, but I missed, I think we should take them out so that they don't flank us, because that would be bad. And if we die, then our reinforcement count will go down. So if you have a gun, you should shoot the enemy, who happens to be in the left, hiding in the stairwell"