People tend to respond better to offers of carrots rather than threats of sticks. The UFC could heed this simple lesson and focus less on hunting down and prosecuting stream jackers who mirror fights online for free and instead focus on making a more compelling argument to not jack the stream (why yes, that does sound filthy).
Add an extra value to the purchased and legal stream, a free tshirt from the event, xx percent off an item at the UFC store, access to archived fights, 15 minutes in a closet with ring girl Arianny Celeste. I don't know, I'm just brainstorming. Anyway. The way to more buys is to look at the good side and see what can be done to encourage more of the good and not worry so much about the bad.
There will always be pirates and there will always be people who either refuse to pay or can't afford to pay the high price of the PPV events, especially when there are sometimes two or three of them a month. But giving people with legitimate means a more compelling reason to buy the PPV would result in greater buys, stronger customer loyalty and would work to expand the UFC brand (not that the UFC needs any help in expanding right now, they are growing like wildfire!).
Value adds are a way, way better incentive than fear of prosecution for piracy (because, let's face it, pirates are cool).
The other thing that doesn't get talked about too much is that some of the UFC cards are pretty mediocre in terms of match ups. But those fight nights still cost the same as every other one, even the big blockbuster cards. I'd like to see the UFC approach their pricing a little more honestly and price the not-so-awesome cards accordingly. And put more of the prelims on the air, either on Spike or online, for free. You want to gain viewers by pulling them in with the undercard so that they buy the main card. Heck, you could incentivize them with a deal for watching the undercard (and the ads throughout it) and give them a discount on the PPV.
There are an awful lot of ways to play this that don't make the fans into the bad guys here because being overly aggressive in fighting piracy just ends up pissing off the legitimate fans.
I remember reading about one argument for DVD piracy in a little infographic. It showed all of the clicks and delays and forced viewing previews in a store bought DVD and then compared them all to how easy it was to play a pirated version of the movie, usually one or two clicks. I've known people who have "pirated" movies they already own just to get around the ridiculous bullshit previews and unskippable crap before getting to the movie.
Last thought, if your customers are pirating your content then that's a failure on your end, not theirs. They want it but you've either made it too hard or too expensive to consume. The UFC has a great product and produces excellent shows with lots of interest (though a little less Joe Rogan wouldn't be a terrible thing) but they are too expensive and there are no refunds if the event sucks or you get an Anderson Silva clown act fight.