I accidentally consumed a coworkers yogurt cup once (and told her/replaced it as soon as I realized). I had started daring a different coworker and she had said something like "you can eat my yogurt in my yellow bag at the front-left of the fridge". Unfortunately, we had 2 fridges in the break room at the time...

Another HN user offered a story (that doesn't seem super unlikely) that would disagree with you:

https://news.ycombinator.com/item?id=16944591

You don't consider that an odd circumstance? I do, but maybe it's more common than I expect.

I mean I'd say it's odd but if you're going to have a rule that immediately results in people being fired you have to think of odd/edge cases.

Depends if you have an oldschool wife who packs you a lunch, and you didn't bother to ask if it was bologna or tuna.