There, mafia doesn't have any business commonly associated with them. Mafia does loans, racketeering and vice. Large industry isn't about any of those things. Maybe I'm wrong but I think you should not overextend the meaning of term "mafia".
Anyway, this does not answers the "fair" question. Oneself fairness is not direcly affected by people the person in question has to deal with. You still have to prove unfairness, "he was seen near where the mafia usually manifests" doesn't cut it.
I'm not arguing just for a purpose of arguing. I'm trying to challenge your idea of "fair rules". If we would not find even one person in this subset who plays by "fair rules", (and you seem to imply there are indeed none), how do we know that "fair rules" exist? Who sets those?