I don't mean to disrespect anyone here but isn't the object to make the bad guys dead and not just scared?
Let me answer this directly, even though it has been hinted at...
In my experience, the use of deadly force was rare. The use of physical force to back people up off gates, or vehicles, or to just keep them at a safe distance lest they get whacked in the head with an axe handle was far more common. In countries like Somalia, people aren't scared of guns, particularly when they are in the hands of nominal peacekeepers. It's an uneducated country, but that doesn't mean they are stupid. I suspect most Somalians knew pretty clearly what the boundary was before we started shooting, and they very rarely crossed that line.
I was in situations there that were pretty hair-raising, but that would have resulted in immediate criminal prosecution had I started shooting. There is something called the "rules of engagement", and you have to know what they are before you start shooting. Not only that, but at least in that deployment, they were fluid, meaning that they often changed daily. Follow them, you are golden (hopefully), ignore them, you are hosed. This doesn't mean that we could just go around cracking people in the skull willy-nilly, but it did mean that if we had a group forming at a gate that would not disperse, we could take steps to disperse that crowd without shooting people left and right.