You can't fake diarrhea.
These f*rs gave me VEAL parmigiana when I'd ordered CHICKEN. Until then, I'd never eaten veal and had no desire ever to do so.
I was so upset and the best both the waiter and manager could do was apologize, say they'd take it off the bill (they better!!! I had two bites!!!!!!!!!!!!!!!!), then launch an explanation as to how, on a busy night, the kitchen could make a mistake.
I don't care WHY it happened. That's the restaurant's business. I care THAT IT HAPPENED. Unconscionable.
To top it off, I had total food poisoning that night and the following morning. Yes, I was completely nauseated that I'd consumed veal, but this wasn't psychosomatic.
Like I said, you can't fake diarrhea.