Contrary to what some posters above have implied, if this article is to be believed then it looks like Taft administration had to be dragged kicking and screaming into calling the police:
It looks like Ms. Porter tried to obstruct the hallway (“50+ student participants”) with the protest (were classes disrupted, too?), and skipped her classes, and encouraged others to do so (“I didn’t even let my teachers know what I was doing and I was not penalized”).
Finally, Taft relented:
http://thevigornia.com/761/features/taft-sits-down-for-racism/
Honestly, Taft doesn’t sound like a good environment all around. No surprise that the administration was reluctant to get the police involved. Just looking at the statute quickly, I think the actions might not even be criminal (depends very much on whether writing on a bulletin board designed to be written upon is “defacing” within the statute - probably - and whether the board constitutes property of the student - doubtful), and if so they are likely 3rd degree misdemeanors at most. Even if the actions were clearly criminal, all these boarding schools will attempt to hush these sorts of things up, as we have seen countless times in sex harassment cases. The Taft administration might also have suspected that it was a hoax.