I don't think it's kids. That goes quite a bit further than a school kid prank. They got some real sick-o's there.
It's three CD players, some duct tape, and timers of some kind. I don't think you give high school kids much credit. We're talking about the only people in the room who can figure out how to program a VCR or get an X-Box hooked up in the mass of cords behind the entertainment center.
When I was in high school some 'kids' stole a bunch of cows, painted them green and put them on the football field. Some other kids landscaped the faculty room, with shrubs and dirt and beauty bark. Simpler and more juvenile pranksters put pipe bombs in garbage cans.
In this one... no one got hurt, they just shocked people. Not a hate crime, not sick, just petty juvenile crime stuff.