Reading about your topic made me realize that these things may do happen in real life, although we do not know for sure if these kinds of scenarios do happen or not. I'm not a sports enthusiast or UFC fan but I'm sure that the sports organizations have preventive measures such as regulations to ensure that these kinds of scenarios would not happen in their sports because it would ruin the organization's integrity and reputation as well as their player or fighters.
Yes, that's happen in real world but we don't knows for sure because that practices is hidden from public and not many people will knows. They are smart enough to hides their activity to makes the scenarios works for them without public knows so they can gets the benefits from the scenarios. We as a viewer only knows that the match is fair enough and not have that bad practice but the reality is we don't knows what happens to them. Some people gets the advantages of what they did and maybe the organizations doesn't knows about that or only some people inside the organizations knows about that practice. It will ruins the organizations reputations and integrity if the public knows the truth and the public will demo so the organizations can do prevention of that such practice.
Match fixing has always been an issue when it comes to competitive sports and betting. It's as old as one can imagine and whatever issues our scenario imagined is actually a very big possibility.
I would like to think that this fixing of matches may become more prone in regions where it is like a major career and for those who enjoy placing a bet on such matches, it would be wise to research the region and cases of such previous happenings before betting huge.
It also would be a wise decision to bet on both sides if there's enough cash or better still, half the original amount intended to bet with on a single player (for boxing matches)and bet on both to win whichever way, incase there's suspicion of match fixing.