One of recent posts here reminded of story from my father. English is not my mother tongue so please ignore mistakes in writing.

He worked in a factory in Eastern Europe and event occurred somewhere in 1980's. I know how weird it looks now in 2020's, but at the time it was pretty common that workers in factory would come to work drunk or they would drink alcohol at work. My father was not much different and he would occasionally bring a bottle of brandy and keep it in his locker ( something similar to this https://images.app.goo.gl/mhFG7kH8zyeyM4R67 ).

These lockers were pretty easy to access without a key, you would need just a screwdriver or some piece of metal and door would be easily bent and returned to original afterwards. The factory was working in shifts and when you come next day, you would just notice that someone opened your locker and something is missing that you left inside a day earlier. As my father was bringing quite good booze it would be missing next day. After who knows how many times his booze was stolen, he had enough of it and he decided to set a trap for thief.

The brandy he usually brought was color similar to whiskey (due to being matured in oak casks) and he took an empty bottle to the toilet and fill it with his urine and locked it back to his locker and went home after his shift was over.

As shifts were slightly overlap (there was no break in factory process), next day when he would come to work, people from previous shift were still there. He came to his locker and noticed that bottle was completely missing. He came to the work space and loudly asked if anyone knows what has happened to the bottle with urine from his locker. He said that he had to go to medical check as he might have some urinary infection and he had to bring morning urine, but he have forgotten it in his locker day earlier.

One of guys turned red and started yelling at my father how he dared to leave urine in bottle labeled as brandy, that someone could have mistakenly drink it and get seriously sick.

After that his locker was not robbed ever and that guy have gotten new nickname - a piss drinker.