I imagine that if these hacks where officially sanctioned and supported by the administration then they'd lose a lot of their charm and appeal. I also imagine the crackdown is more for show than any actual serious attempt to stop them.

Also sometimes kids get carried away and cannot fully think through their actions. My university had to crack down on these sort pranks or hacks after they escalated to the point where one caused several thousands of dollars of damage to public property . Just because you're a "genius" doesn't mean you have much common sense. However the crackdown wasn't an all out ban just stern warning that being stupid about it wouldn't be tolerated.