There was a whole movie about using this tactics, long before computers got widespread. The plot was built around some trickster who separately challenged two chess champions which hated each other. They agreed to play against him as well as lose substantially more than win since they innocently believed they could easily smash to pieces their insolent opponent. While in fact they turned out to be playing against each other at the end of the day. I don't remember the movie title though. Anyone know?

The trick is not new. Alekhine and his twice world championship challenger Bogoljubov are said to have been challenged separately to games of correspondence chess at money odds. In effect the opponent, who had little chess skill, was playing in neither game. He was simply passing on the moves of the players. Since he had received money odds he ended with a net profit whoever won the game.