Scamming on prop bets, like Rozier appears to have done, I would think is pretty easy to catch. If suddenly there is an uptick in action on Terry Rozier going under 15 points (or whatever) the books can see that. Maybe normally, there is $10,000 being bet on Rozier props but then suddenly, for one game, it jumps to $300,000 and in that same game, Rozier limps off the court in the 1st quarter with a mysterious injury. That is going to stand out to the books.
So for this reason, I don't think this type of scamming is rampant. Betting on the outcome of games, over/under, point spreads, would also have the same issue. If there was a sudden increase in the action on a particular team or ref or something, it would show up. And I think you would need to have more people involved. Can one ref for example, make sure a team wins by a certain number of points? Can one player? Seems harder to do than the individual prop betting manipulation. One player can make sure he doesn't get more than 5 Rebs or whatever. Or limp off the court in the 1st quarter.
I get your logic, but I'd point to Tim Donaghty. He cheated for years without being caught.
I don't know all the details, Donaghty must not have been betting all that much money. My logic was intended to support my point that this is "not rampant". Not rampant is different than never happens. Are you suggesting that this is rampant? How do you define rampant? Every game every night? One or two games a night?
It is an inherent problems with gambling, there is going to be some of this, even at the professional level. Small time stuff can go under the radar for sure. But people always get greedy and the bets always get bigger, and that is when it will show up. If one rogue ref wants to make himself an extra $100 or whatever every game, it will be hard to trace that level of bet, especially if the rogue ref is smart enough to use different books. But if this rogue ref is tied up with more organized criminals, and the $100 bets start to become (20) $1,000 bets, that will show up.