I was just thinking about one result of last year's betting scandal. Remember, it was betting on baseball, not sumo. But it was sumo wrestlers betting on baseball. Via the yakuza.
Afterwards, the powers that be wanted to prove they were purging the sport of the corruption of mafia ties. Mafia ties didn't go over very well with the fans. So, to prove they were severing any ties (which had never been sanctioned, just existing under the radar), they made a major announcement to all the audience at the beginning of the July basho in Nagoya (if I remember right, that's where this happened.) It was basically, "All righty then, everyone here who is a member of the mafia is invited to leave right now."
Okay. So I'm laughing at the thought of this. Right. I can just see it now. Announcement goes off. A row of fifteen guys in expensive suits perk up, look around, point to their own chests, ask something equivalent to "Moi?", shrug, get up and leave.
Yeah. I love the jokey ineffectiveness of this. It's almost like they were doing it in jest.
Then again, maybe it worked.