From the Wikipedia article linked above:

"The Hillsborough disaster was a human crush at Hillsborough football stadium in Sheffield, England on 15 April 1989, during the 1988–89 FA Cup semi-final game between Liverpool and Nottingham Forest....The crush occurred in the two standing-only central pens... Shortly before kick-off, in an attempt to ease overcrowding outside the entrance turnstiles, the police match commander, chief superintendent David Duckenfield, ordered exit gate C to be opened, leading to an influx of even more supporters to the already overcrowded central pens."


A human crush -people pushing shoving hurrying, each one wanting in. The crowd getting uncontrollable so fast nobody could think. When one person does this, it's bad manners. When thousands do it, it's tragic.

We don't have social strategies for coping with thousands of people being naughty. We can deal with lone criminal, gangs and organized crime, but not with thousands of people committing a misdemeanor at once.