When the Plainedge Red Devils extended their rout last week of the South Side Cyclones with a fourth-quarter touchdown, it was a crowning moment for the winner of a big game between unbeaten high school football teams on Long Island.

It was also the trigger point that led to a more surprising result: the winning coach’s suspension.

Nassau County has an unusual policy designed to prevent lopsided results in football games: If a team wins a game by more than 42 points, the winning coach must explain to a special committee why such an outsize margin could not be avoided.

With that last touchdown, Plainedge pushed the final score to 61-13, putting the team in violation, and subjecting its coach, Robert Shaver, to a one-game suspension.

The committee determined this week that Mr. Shaver, who became the first varsity coach to be punished under the three-year-old policy, should have pulled his starters when he had a big lead at the start of the fourth quarter, and it found his explanation for why he did not lacking.