Agree, it's not the brightest idea, but it is possible.
The difference is, in our sport, there is no "sanctioning body" ... so there is no such thing as a "Sanctioned Match"
For example, in boxing, the WBC (let's say) must sanction a match in order for it to be counted in the books as "legit." In other words, two people can't just challenge each other and have their fight go on record.
However, no such requirements exist in our sport, precisely because there is no sanctioning body. Therefore, any 2 people wanting to place a bet, agree on a weight, a ref, and a timekeeper, can create "a match" ... and whoever wins or loses is a "winner" or "loser" of "a match" ...
Jack