It’s happened before. In 1979, 11 people died while trying to rush the door to see the Who in Cincinnati. In 1991, a crowd crush outside a Puff Daddy-promoted celebrity basketball game at New York’s City College killed nine people. In 2000, nine people died at Denmark’s Roskilde Festival while Pearl Jam played. In 2010, a crowd stampede killed 21 people outside the Love Parade, a German dance festival. It’ll probably happen again, too.