Q. Since notes must be confined to game state, what actually constitutes "game state"?
A. Any notes you take during a tournament must be confined to changes in the game state and taking those notes must not slow down the game. Game State includes things such as number of Prizes remaining, number of cards in hand, whether or not a Supporter has been played, whether or not a Power has been used, how many of a specific card an opponent has in his/her discard pile (this does not include listing the entire contents of the discard, just a simple "2x Rare Candy"), etc. Game State does NOT include which cards are in your hand, which cards are in your opponent's hand, which cards are in your Prizes, which cards aren't in your deck because they are in your Prizes, how many licks it takes to get to the center of a Tootsie Pop, etc. (Dec 18, 2008 PUI Rules Team)
Q. Can I take notes in code or make deceptive notes during a match?
A. Per the Tournament Rules, your notes must be taken timely, restricted to changes in game state and open to review by the other player. Codes hinder both review and timeliness, because you have to explain them to the opponent. Of course, dubious game actions intended to deceive the opponent may earn a disqualification for unsporting conduct (i.e., no deceptive notes). (Oct 16, 2008 PUI Rules Team)