i know a little bit about this cause some of my coz where bouncers for some night clubs around the Goal Coast (Australian reference). both of them thought very hard about whether or not they should get their license and carry them around for there job. since there are plenty of stabbing and such in their line of work. but both of them decided not 2 mainly cause of 2 reasons.
1) it is very difficult to keep an eye on ur firearm all the time, nearly impossible. this leads to a point where it can be stolen from u and used against u. now is it so smart to carry one around? even if they don't know how to properly use it and they do shot some1 u r responsible for it. not very wise if u ask me.
2) this one mainly about the shear cost of carrying it around over here. got very tight restrictions.
but America's type of thinking is seems to run along these lines "a strong offense is the best defense" but that not always the case.