This is a rule set in place to prevent or nullify complaints of people running up the score. It's simple, if you are to a point where the game is out of hand you simply DM your opponent saying "white flag" and you both begin to chew clock and call only running plays. An opponent does this when the game is either out of hand or they want to get the game over with. Basically if you don't want the score ran up then wave he flag, otherwise both of you play your type of game without holding back. This way there are no complaints of score being ran up bc the user has the ability to stop it from happening by conceding.
This rule is from two other leagues I'm in. It is regarding the pass within the numbers. The rule states that if you pass outside of the numbers at any point on the field and you complete the pass the user must either punt the football to the opponent or if in field-goal range you kick a fg. This is their way of making sure that the pass within the numbers rule is enforced because without it users can pass outside the numbers with no repercussions.