A story from when my wife ran the business office in a car dealership. The dealer was given to exaggerate if not outright lie about things in the managers meetings with the managers of all the departments. The managers devised a way to alert the other managers when he would start talking about something that they knew was not true. Whenever this happened, they would alert each other by lightly tapping the end of their pencil or pen on the table. He never found out what was going on if he ever even noticed.