Teams

Only players with a minimum amount of experience should be allowed to join team games. It could be something like played > 25 games or skill level > 2. A player who isn't comfortable with the normal no team format will have a hard time in a team game and may ruin it for their partners too. A minimum level of experience will ensure they'll catch on quickly even if they're playing a team game for the first time.

Also, maybe there could also be a minimum level needed on their "Attendance score" so as to ensure they take won't be skipping too many turns and ruin the game for their partner.

I'm not too sure about the attendance suggestion but the first one I feel is needed. Thanks.

You can set your own points limits and password protect the games if you choose to as well.

Only premium players can set point limits. Also with passwords I'll have to manually invite a lot of players and keep a track of who's joining and who's not.

If there is an existing limit then one can create a game and be assured of the fact that no one is ruining it.