This needs to be resolved.
As someone who's been shot at, and been around people shooting guns off... it's incredibly difficult to locate the exact position of a shooter who is concealed. Generally muzzle flash or other visual clues give the shooter away. In the game, the simple firing of the gun (say shooting at a group of 5 guys without hitting them) causes them all to aggro.
I can't imagine you guys aren't annoyed by this.