I would like to go with follow up.

I sent this text to support and received positive answer, that they would suggest this idea to devs.

Now I would like to expand idea.

To prevent abusing this feature, I would suggest to set limit for amount of games like that could be played. Let's say 1 game in 3 hours.
Also would be great if spectators can join game to watch, without ability to support any team. This way tournament participants can watch and enjoy important/interesting games.

Also I suggest to leave this type of tournaments for community, and not build anything inside game itself. On facebook now it's building very strong, big community which will drive furter popularity of this game. With built-in this type of tournaments it will be lack of communication between participants, and will drag it down.