New rule:
If teams write "illegal" under their illegal deck in the round deck topic, they will automatically forfeit the match, BUT don't take the 6 card penalty for building an illegal deck. By adding "illegal", teams show that they knowingly built an illegal deck, and can prevent a situation where they would be forced to take a double penalty (both discarding because of a loss and a card penalty) for not being able to build enough legal decks.
As usual, if teams build an illegal deck by mistake, they will take the 6 card penalty.
If you have any questions about this new rule, please let me know.