I like striker’s idea about a restart but I don't think that would ever be possible. I would think 12 players on field would be a RED card. Should play a man/ woman short. I know if you walk off the field with out a proper substitution then you will receive a Red Card. This happen at a game I was coaching. Coach yelled at one of his players to stop being lazy and the kid instead of responding to his coach just walked off. Kind of funny but the team was punished by playing a man down