Content pirates are not really pirates in the sense that they have any kind of reasonable defense in the event they get caught. Real pirates can fetch automatic weapons; Internet stream owners tend to be less formidable.
The UFC’s ability to shoot fish in a barrel that actually come up for air is not contestable: where they will continue to have trouble is in locating, identifying, and prosecuting the sites that operate far under the radar of a conventional Web presence. The really guarded probably hide IP addresses and shift their base of operations around; their viewers are probably sub-casual fans who wouldn’t pay for a show otherwise. (If they were obliging fans with money woes, they’d probably just go to a bar.)
The UFC had six of the ten highest-grossing pay per views of 2009; boxing continues to tick off record buys. As problems go, piracy runs a distant second to fighter pensions, insurance, or any number of productive ways you could spend the money lawyers devour.