Well, I don't know if this would end up giving him yellow/red cards, but the guy that already scored one goal could just play so his team wouldn't make goals in order to make sure he proceeds. I'm not saying the guy on team Z would do that, but it's something that probably doesn't make anyone improve as a player and is a completely valid strategy within the rules set up by Ego. So yeah, players that were ahead on goal scores could just throw the matches in order to guarantee their survival. I haven't read ahead yet, so if it does happen it will be interesting, but I doubt it.