In my eyes the question is: would the audience carrying side arms lower the chances of the extent of the body count.
In my eyes, the question is: What sort of mayhem can we expect if everyone carries a firearm?
I won't dispute that there are people living in the USA that take firearm ownership seriously, go to firing ranges, and are generally good all around people. I also won't ignore that there are people who, while not criminals, aren't exactly the great of people and should definately not be allowed to carry a loaded weapon.