Dangerously unpredictable manufactured pop sensation Justin Bieber was "horsing around" with some friends before a concert when he threw two water balloons at Maryland State Troopers, one of which burst. Biebs, assaulting a police officer is a felony!
You're not in soft-on-crime Canada anymore, kiddo! You could get locked up for ten years for that shit, meaning when you were free again you'd be 26, therefore old and wrinkly and useless. Sure a police spokesman said that the "inappropriate behavior" would not be prosecuted or anything, but you never know. Those cops can be sneaky! Maybe they're just trying to get you relaxed before they pounce, J-Bieb.
So in the future: Even if you're just trying to exact water vessel-related revenge, don't throw water balloons at cops. I mean, there's no need. I'm sure you have plenty of civilian fans who would be thrilled to have you hurl fluids all over them.