Gibberish names. I bet this is intentional and the admins are unable to block users from doing this. And ignore list will not be able to handle this - just create a new user every once in a while. As long as the free scrolls last.
Due to the karma starting from MAX for all players, any user can come and ruin the games of good players.
And due to the matchmaker being so bad, it is hard to block bad players from coming to your games.
This platform is just fundamentally broken.