Just look at that clever idea. You keep your coffee cup at work and keep having them stolen. Put in the included key and fill it up. Walk off and put the key in your pocket or purse. The thief will find it hard to put coffee in and drink it.
I found another useful invention. It is sandwich bags with mold printed on to both sides. The thief thinks the sandwich is moldy, is also lazy and won't eat your sandwich.
I have tried that. Now, this is no new invention, but around age 20, I once lifted up the front of a very small car and got help to put the front on blocks. I guess when the owner came to pick up his car after his shift, he was not pleased.
I worked at a large plant, an Industrial laundry, I bought my lunch, at a diner, two flame broiled burgers onion rings, and cake, a coke, I was called to repair a machine,, came back and found a plant worker finishing my lunch !! This was in the maintenance building he had no buisness being in !!!
I worked at a few places where a lunch could be stolen. Fortunately nobody stole my lunches. It has to piss a guy off to have his lunch stolen like that. I would have reported the guy to supervision. I hope you did. Something i have never seen get brought up on any forum. When i worked at the GM plant in Fremont, CA in 1964, workers would take their lunch time to get to their cars and engage in sex.
I did not want to get him fired. I was however, plenty mad. He was always talking about money as if he were rich, yet the only meals you saw him eat were charity.
It happened perhaps once a month, the maintenance building, the doors were locked after, only maintenance personnel having entry after the fact. Any bag lunch or diner food would vanish if not eaten quickly, and it was plant workers, you would latter find the evidence in a plant waste bin.