"At the entrance to the Berkeley campus, authorities distributed leaflets saying that the following items were prohibited because they could be used as weapons: bicycle locks, frozen fruit, balls, laser pointers, plastic water bottles, skateboards and balloons."

http://www.sfgate.com/news/article/Protester-at-UC-Berkeley-who-refuses-to-remove-11104429.php

Weaponized frozen fruit, folks. Stay safe out there.