On a personal note, in one game during my youth we were slaughtering some team 30-0 or so... They managed to score a long touchdown, but were flagged for a penalty. We all jumped up and down at our good fortune and as the captain, I ran over to the ref signaling that I didn't want the touchdown to be counted by using the arm gesture for declining a penalty.
Instead of confirming with a 10 year old kid of his intention, he signals the penalty as being declined and the touchdown counted.