Every man in a village of 100 married couples has cheated on his wife. Every wife in the village instantly knows when a man other than her husband has cheated, but does not know when her own husband has. The village has a law that does not allow for adultery. Any wife who can prove that her husband is unfaithful must kill him that very day. The women of the village would never disobey this law. One day, the queen of the village visits and annoces that at least one husband has benn unfaithful. What happens?
Nothing happens. The queen does not tell the wives anything they don’t already know. They know that the other husbands are cheating, so it is not news to them.