At 7:30PM, while the kids were in the middle of building a rock castle, a schoolmate of my 10 year old kid came to our home. She ran away from home, and so she came to the home of her best friend. How logical.
Immediately I thought of the Prisoner’s Dilemma. If your kid runs away from home and drops by at a friend’s home, you would like the friend’s parents to host your kid. But you yourself are better of sending your runaway child’s friend back to his home, or letting him find another friend to host him. So this game is the Prisoner’s Dilemma: sending the friend away is a dominant strategy, but both parents prefer that they both host each other child to having both kids stroll around in the streets looking for a friend with friendly parents.
I did not need to analyze the game to know that what I should do, and I sent an SMS to the friend’s mother telling her that her precious daughter is safe and sound. It is left to see when the runaway kid will decide to return home.