Carrying a gun does nothing with the exception of to frighten the harmless and make the not so harmless nosy. You need to know how to handle it and have the will to use it. The latter two are usually void, so in the end it is harmful to the owner. And in most countries all three are illegal anyway. Owning a gun, carrying it and having the training all usually require a license. Let alone using it against other people in any place is a thing not for the faint of heart.