This is not anything too new really. Most leagues have some sort of rule when it comes to scoring in youth football. Some are tighter than others. My sons league has rules and these are directly from the conference Web site, not as tight as this situations, but still rules in place.
Once a team has scored a 30 point margin in a game, no player may play in his/her normal position until the 30 point margin is reduced.
Once a team has scored a 30 point margin, the game will go to an automatic running clock immediately after the second half begins. The clock continues to run even if the 30 point margin is reduced.