I regularly have people supporting my opponents. Of course it doesn't do them a whole lot of good. My main rival doesn't do this and I leave his games alone as well. He is the only one within a star of me in all 3 competitions.

Outside of my one game so far against my rival I have yet to have less than a 10% advantage in any game and that was when I missed my game. When I am watching it is usually between 60/40 and 80/20. I have a 40 game unbeaten streak dating back to last season

I have people in my friend list who show up against me in the cup/cl mainly and I'm not mad at them. If I was 2*+ below the best team in a cup I would be praying he would lose too. Good luck to em, if I lose it will be in the league or a final.