Murphy and his wife, a middle-aged couple, went for a stroll
in the park. They say down on a bench to rest. They
overheard voices coming from a secluded spot. Suddenly Mrs.
Murphy realized that a young man was about to propose.
Not wanting to eavesdrop at such an intimate moment, she
nudged her husband and whispered, "Whistle and let that
young couple know that someone can hear them."
Murphy said, "Whistle? Why should I whistle? Nobody whistled
to warn me."