Really?
Like the guy last week who shot several people in a store that specifically allowed open carry?
Or where the shooter goes for the armed security first?
Or where the police nearly (or do) shoot the armed non shooters, and waste a lot of time trying to work out which of the people with a gun was shooting and who where they shooting at?
It's a myth the NRA seem to love to push that the shootings happen in "gun free zones", in reality it doesn't make much difference, except in terms of how easy it is for the police to work out who is the shooter, and how much of a chance you stand of getting hit by a poorly trained, panicky "defender" who has bought a gun but doesn't know how to use it in that situation.