Game plan and "cheat sheets"

[Shad0w]

Actually, in most games, magic for example you are allowed to bring outside notes within reason. Such as like, I'm playing against X, this deck usually has X threat that destroys me. Etc.

The rule was changed again double check the MTR


2.11Taking NotesPlayers are allowed to take written notes during a match and may refer to those notes while that match is in progress. At the beginning of a match, each player’s note sheet must be empty and must remain visible throughout the match.
Players do not have to explain or reveal notes to other players. Judges may ask to see a player’s notes and/or request that the player explain his or her notes. Players may not refer to other notes, including notes from previous matches, during games. Between games, players may refer to a brief set of notes made before the match. They are not required to reveal these notes to their opponents. These notes must be removed from the play area before the beginning of the next game. Excessive quantities of notes (more than a sheet or two) are not allowed and may be penalized as slow play. Players and spectators (exception: authorized press) may not make notes while drafting. Players may not reference any outside notes during drafting, card pool registration, or deckbuilding.

Players may refer to Oracle text, either electronically or in paper form, at any time. They must do so publicly and in a format (such as gatherer.wizards.com, other official Wizards of the Coast sources, or printouts of their sources)which contains no other strategic information. If a player wishes to view Oracle text in private, he or she must ask a judge. Artistic modifications to cards that indirectly provide minor strategic information are acceptable. The Head Judge is the final arbiter on what cards and notes are acceptable for a tournament

[Hanma]

Oh, huh, touche sir. I could have sworn you could, this is what I get for posting a thought without googling for evidence.