“Where does it say that I have to let you switch every time? I am the master of the show.” Monty made it clear that the rules of the Monty Hall problem do not apply to him. “If the host is required to open a door all the time and offer you a switch, then you should take the switch. But if he has the choice whether to allow a switch or not, beware. Caveat emptor. It all depends on his mood.”
