Yeah, I also thought that including everyone in the game, without them even knowing that is kinda annoying.
Well, now you can fix that!

Using /exclude you can exclude whoever you want from whatever game you have!

Usages:
/exclude <gameID> <player> [add -r to remove]
> Adds or removes the player to selected game's exclusions.
Example1: /exclude biathlon1 Notch > add Notch to exclusion list of game biathlon1
Example2: /exclude biathlon1 Notch -r > remove Notch from the exclusion list of game biathlon1

/exclude <gameID> view
> Prints out the list of excluded players for that game.

/exclude <gameID> clear
> Clears the exclusion list for that game.