This actually makes a lot of sense. You're saying if everyone has a gun and everyone knows it, then who's going to bother one person? this kind of goes back to the point of self defense, but this idea is more of a fact that if you know if someone has the ability to defend themselves, a potential attacker might be deterred from attacking a person because the attacker might become the one attacked. This is why a woman might carry a can of pepper spray in her purse, or how a security guard carries a baton, mostly for looks. I witnessed this first hand when I went to Haiti once and in the area where we were staying they hired a security guard to walk around the courtyard armed with a rifle to keep us safe. They said they never had a problem with people breaking in and causing trouble, because who could bother a guy with a rifle? I also witnessed this in a museum we went to in Haiti, there were several men with rifles and I don't know a single person who would try to cause trouble there. this is why I think this is a legitimate reason why more guns would actually help