We have something that we have affectionately named "The Portable Appliance Tester Control Under Non-standard Tests" device. I would post the acronym but fear the forum filters might pick up on it for some reason. Anyway, it's a 4-foot length of 2x4" wood with a 6-inch nail driven through one end. We have a notice in the server room that basically says if they so much as look at one of my servers they'll end up with it wrapped around their head. Yes, a prison sentence would probably lie in wait, but I'm confident that would be easier than the carp I'd have to deal with if a server got fried. For added measure though, our server room is locked, and all servers are also in a locked rack - nobody is getting in there without my say so.