When you organize a tournament (accessible in the left panel, "Tournaments" tab, by clicking on one of the tournaments and then on "View"), you have a responsibility to address potential problems reported by other players. In the tournament profile, the action "Reported problems" records reports made by tournament participants. Moreover, whenever a new issue is reported, you will be notified in the notification area (at the bottom of the left panel). In case of cheating, you can review the game, download the game in "pgn" format to verify and if appropriate, disqualify the player, award the points of the game to the opposing player, and recalculate the scores of the tournament, if you feel that cheating is proven.