Examples: 1. More or fewer cards than appropriate deck size. See 402 for more information about deck size. 2. Cards not legal in the format of the tournament. 3. More than 3 copies of a main deck card between main deck and sideboard. 4. Cards that do not match the domain of the registered legend. 5. A chosen champion that does not match the identity of the legend. 6. A player’s decks contain cards that do not match their registered decklist.
§ 703.3.a Tournament Rules PDF (officieel)
§ 703 Tournament Errors
§ 703.3 Decklist Error [Game Loss]: A player submits a decklist for registration that contains illegal elements.