I live in Wisconsin where concealed carry is illegal to any civilian, but open carry is legal except 1000' from a school, businesses that post"NO GUNS", in vehicles, and Gov't buildings. Now because concealed carry is illegal and people don't know their rights to open carry, the general public here which is mostly "anti-gun except when hunting" goes nuts when they see a gun. I will take the other side and say, IF this happened in my state and you drew down on a man getting out of a car who then loaded a gun, rifle or not, then you drew down on a citizen LEGALLY exercising his right to bear arms. It's illegal at the point where he brandishes the gun in a threatening manner. While a long gun may be overkill for defending yourself in public and I admit doesn't look right, it is perfectly legal, here anyway. Hell if signs aren't posted, you CAN walk around the mall with it. The sad part is that most of the people I know, gun-owners even, do not know they can open carry.
Jrdudas had it right, if these people KNEW there were multiple people 'packing' around them, then they wouldn't try it there. The fact is that there isn't enough money to have trained, armed security or cops everywhere, and you shouldn't have to take the chance that there will be. Knowing that everyone around you is a mother, father, son, daughter, to someone is enough for me to know how I would face the situation. I think a conviction would be hard to get when everyone knows you saved lives. And gun-free places take no business of mine.