Six Flags not so safe?

How could anyone get stabbed at a park as safe as Six Flags? I mean, they have policy in place and everything; see, it says no knives:

PROHIBITED ITEMS
In addition to all items previously mentioned, the following items are not permitted at Six Flags America, at any time:
Lawn chairs and folding chairs
Magic markers, spray paint and aerosol cans
Glass bottles
Knives
Spiked clothing or jewelry
Fireworks and explosives
Firearms and ammunition
Chemical weapons, including mace and pepper spray

I'm terrified of the spiked jewelry, and the magic markers just make sense because you never know when some kid may get the urge to see if it smells good or not. You just can't be too safe these days.

Being defenseless is great!