Sports are big business these days. There's so much at stake for each team and individual - not just glory and a shot at the record books, but billions upon billions of dollars. What this means is that people will do anything to win. From doping to match-fixing, we've seen everything tried, and many attempts exposed, in the quest for a huge purse. But the massive boxing match between Floyd Mayweather and Conor McGregor was above all that. Or was it?