At a guess, by pointing out the "Gun-Free Zone" signs. Edit: No longer a guess, https://babylonbee.com/news/chicago-schools-gun-free-zone-sign-riddled-with-bul

At a guess, by pointing out the "Gun-Free Zone" signs. Edit: No longer a guess, https://babylonbee.com/news/chicago-schools-gun-free-zone-sign-riddled-with-bulletholes https://babylonbee.com/news/chicago-schools-gun-free-zone-si...