Two of my children are not talking to me after a fun family game of Cluedo. For example I am sitting holding the cards for the rope and Mrs White. Child A says "Mrs White, in the Dining Room, with the rope". Child B shows child A a card. Because I know I have two of the three, then, I can now cross the Dining Room off the list as there is no other car it can possibly be.
This is apparently blatant cheating, against the spirit of the game and causes meltdowns. 