The major problem is the big promoter hiring judges for an event because of knowing he has the guy in the bag. Lot of promoters know their judges very well. Inviting them to big partys, hotels, weekends and such stuff. Sending them gifts to birthday and other occasions. It's a corrupt business. You can only improve this with sending random judges to random events. For example Californian judges going to Florida and juding an event. NYC judges going to CA to judge. But ...this would cost a shitload of money and nobody would do that.
That's just buttering them up. They shouldn't be partying with promoters they are there to judge a fight. Nor Receive lavish gifts, dine with fine wine and in 5 star restaurants,.Now we know why even international judges get buttered up even before the fight starts.
Yeah, but how you can prevent it? If a Promoter wants to invite a judge or send him a gift, you can't prevent it.