Rules would hereby follow:
In order to sub, a player must be registered on a team in the tournament.
A team is allowed to use 1 substitute player from a player pool of players registered in the tournament.
A team is allowed to ban 1 sub player from participating in a game.
This ban is removed every time that specific player leaves the game.
This ban remains in effect if the player rejoins the game and the team who declared that player banned does not specify another player to be banned.