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.
True, we as spectators only know everything in general that is published and maybe we just know about which players have a high probability of winning the fight or match without the slightest thought that leads to the cheating scenario, but yes, however unexpected things like that are very possible or have the potential to actually happen but maybe I think such scenarios are quite rare because the problem is that it is impossible for a player or fighter who already has high flying hours and good popularity to sacrifice everything they have worked for just for money.
Although for example the public does not know about what really happened behind the scenes but still the defeat experienced by their favorite player will indirectly cause considerable disappointment and obviously this incident can make supporters put a bad point of view on players who pretend to lose just for money, which means that the player's popularity will at least definitely experience a decline and I'm sure most players don't want to sacrifice their popularity just for money alone.