Many years ago, I was a poor, struggling college students in one of these leafy private schools in the south that thinks and bills itself as ivy league. I lived in the dorm with all of my other dorm rat friends and kept the same insane hours--sometimes up all night studying or doing the same nefarious things all college students did in the '70s. The only break available was a trip to the vending machines at the bottom floor of the dorm, and all too often, the machines happily took quarters (then) and gave----nothing in return. The university was notably unhelpful in getting money back, saying that it was the responsibility of the vendor--in this case Coca-Cola to make refunds. and they blew us off as unimportant kids and never came through with product or refunds. Many $$ in the hole, I decided it was time to teach them a lesson. The big vending truck (a tractor-trailer) came once a week, and since the drink machines couldn't hold that much at a time, they filled the machines and put all that glorious excess of Cokes, Sprites, grape, and orange drinks in a big welded cabinet with an imposing looking padlock on the front. College-kid proof. Or was it? I had a big master lock with a little wear and tear on it that looked like theirs. When they made the first trip back to the truck, they left their padlock unlocked. I swapped their lock for mine. When they finished filling the cabinet with all of those glorious cases of soft drinks, they clicked the (my) lock shut.
Late THAT night (remember we were night-owls), my roomies and me went back to the cabinet, relieved it of all of those cases of tasty sodas, took them back to our room, which became the dorm distribution point for all the varieties of soda from their storage cabinet. I then replaced my lock with their (open) padlock, snapped it shut and went on.
When the asshole vending guy came the next day to replenish the machines, we peeked out from cover to watch him open the cabinet, close the cabinet, and open it again. Classic double-take; he could not believe his eyes---where did the soda go? Shit went down shortly thereafter, with all kinds of new policies and procedures--but we all had decent stashes of soda to show for the escapade. They never figured it out. The refund policy got better shortly thereafter as well. It seemed like the perfect crime......