This document provides guidance on performing deck checks at competitive REL tournaments. It explains that the main purposes of deck checks are to deter cheating, catch any cheaters, and catch simple clerical mistakes in decklists. It outlines the steps of a deck check, including collecting the decks, checking the physical decks against the registered decklists, noting any issues found, and returning the decks with appropriate penalties if needed. Performing deck checks correctly helps ensure fair play at tournaments.