In a properly rigged fight the winner has to believe they won. The loser is the one who actually has to do the work. When both fighters are in on it like Fox v LaMotta alarm bells start ringing.
Hell, in the best rig, neither fighter knows right? You just stack up a favorable ref, favorable judges, etc.
I don't think you can ensure an outcome this way. What if the fighter whose supposed to lose knocks the winner out or causes damage so the would be winners corner throws in the towel? Whats the ref supposed to do? The loser is the most important component here. Hes the only one who can almost promise the fixers they get their desired outcome.
Many of Carnera's opponents were so abysmal no inducement was needed. Others like Big Boy Peterson and Elzear Rioux were dive artists,some like Stribling ,Godfrey,Lodge and Thomas, were known to do business.
We can certainly bring the charge against Carnera, as we can against most of the other champions of the era. There was almost certainly some business going on early in his career. What I don't believe, is that he ever benefited from a fix, in an fight that had any consequence on a world level. The only fight that happened on American territory, that has any question mark over it in my eyes, is the Godfrey fight.
You don't have to fix a fighters opponents until he gets into world class fighters who are ranked.....you can simply match them with low level opponents who are prone to stoppages or who are struggling financially and out of shape or sick etc.....the idea that a fix only means the opponent lays down for money is actually rare but setting up opponents who can't win or have no desire to be a champ to or have china china etc.....happens all the time even today.
This is just about my belief on the subject, also. And in spite of probable fixes early on, I think Primo learned a bit about boxing fundamentals as his career went on. In the prime of his career I do not think he was really as bad as many think.