I think friendship games should need approve bye both two teams. But the actual is one-sided demand. One of our friends want to arrange a friendship games and you have no choice to stop it if you aren't online. That's a big problem if the user have a serious games, because the condition of players is running.
My suggestion is: All users should have a main option against friendly games. That should be "Yes, I let all my friends for friendly games, except ...." or "No, don't let to anyone to arrange friendly games" etc.