Restaurant Taboos
What is the most Taboo thing you have encountered while in a Restaurant?
I don't know whether this is a taboo, or just bad mannered, however it is extremely rude when people eat with their elbows on the table.
Also in the Royal Navy, just before a meal the Mess President calls "Ease Springs" which signals the last opportunity to use the facilities. Once everyone is sat round the table, noone is permitted to leave, for the toilet or otherwise, until the meal has been concluded with the toasts, and the order "ease springs" is given again. If anyone leaves the table during the meal, they are fined.