I have yet to see any anti-cheat system to detect computer assisted play.
... The only way this might work, would be to force speed chess.
This way the user will be penalized, while he inputs his opponents moves on a electronic device and waiting for the computer to make the
moves for him. People find ingenious solutions to cheat, so a smaller prize pot, would reduce the incentive to cheat.
Well cheating would be hard to stop during the game, however algorithms and machine learning models exist to analyze games for possible cheating retroactively. Thus, ban users cheating. Organize games/tournaments such that they are based on skill and rep.