Amen to that. It is nice to have a place to put your lunch and keep it cold, but it seems like if you put a fridge in a communal area like a break room, suddenly 20 adults (or however many) will turn into lazy disrespectful 15 year olds and do exactly those things. It's disheartening.
I feel your pain. I've worked with fridge thieves and honor box thieves (you know, those little snack boxes where you pick your snack and put your money in the slot on the honor system) and it is really frustrating.
I'm going to say go with the ex-lax instead of Visine, though. Maybe a little syrup of ipecac. I didn't know Visine would cause the trots, thanks so much for that information PP. Filing it away under Future Possibilities. However, I've been told by a Formerly Very Bad Person that ingesting Visine will constrict the blood vessels in your brain and cause you to pass out. Don't know how much it would take, but I'm sure you'd hate to have a freak accident happen (maybe he/she would pass out in the middle of eating some stolen cheese and choke to death).
Really, it's kind of fun dreaming up the possibilities for revenge that won't actually hurt anybody, isn't it? Hmmmmmm.