I have a relative who is a flight attendant. She told me about a flight she was on and a woman came on board with her son who was about five or six. The boy was screaming and yelling at the mother who was doing absolutely nothing about it.

My relative walked up to the boy, leaned down and very quietly said "do you really think that all of the rest of the passengers want to listen to you screaming?"

She said the mother was stunned, but the boy stopped.

She was sure she would have a complaint, but none were made.