Vince Vaughn explains the obvious: how mass killers pick out venues where their victims are sitting ducks

From Vaughn's interview in the UK edition of GQ:

"It's well known that the greatest defence against an intruder is the sound of a gun hammer being pulled back. All these gun shootings that have gone down in America since 1950, only one or maybe two have happened in non-gun-free zones. Take mass shootings. They've only happened in places that don't allow guns. These people are sick in the head and are going to kill innocent people. They are looking to slaughter defenceless human beings. They do not want confrontation. In all of our schools it is illegal to have guns on campus, so again and again these guys go and shoot up these f***ing schools because they know there are no guns there. They are monsters killing six-year-olds."

Media Matters attacks Vaughn by pointing to flawed a report by Bloomberg's Everytown, but of course, Media Matters does respond or even acknowledge all the errors that have been previously pointed out with Bloomberg's report.  See also here.