They cheat by winning players that have won enough matches to boost their rating. They arrange these wins / pay gil to them in order to get as much rating as possible from each win and thus get to the top 3. It was the same in the last tournament. SE needs to change this so that you just match up to against random players or something. I don't know.. I stopped giving a darn about the tournaments because you won't get a card if you happen to get to the top 20 players (I wish you did), only the top 3 get the card and those 3 are hands down always these cheaters, so there's no point in trying to compete against them unless you want to blow a lot of gil to arrange your wins.