Not me, but some old friends. Back when I was in middle school I was friends with a guy and his slightly younger sister, and I went over to their house from time to time.

Now whenever my friends' Mom or Dad wanted something from their kids they would blow this very high pitched whistle from across the house and my friends would drop everything and go scrambling to attention like trained dogs or maybe soldiers. And even when outside the house if they ever heard a whistle sound they would automatically jump up as if they where being summoned.

The parents where nice enough and my friends besides that where completely normal. But it sure was an odd thing to witness.