In Illinois, we use the 40+ mercy rule. The clock only stops on scores, timeouts and between quarters. We had a game two weeks ago, the home team was up 42-0. The visiting coach asked if we could even run the clock during timeouts and scores becuase he had already had two players hurt (it had been raining and the field was wet) and could not afford to lose anymore, even to simple injuries. Our linesman told him that we could not, but that we would do a good job keeping the clock moving. The game ended 48-0, no more injuries, and boy the winning and losing coach being happy, and both showing great sportsmanship.