You might have gotten caught if you watched Mayweather vs. McGregor for free. Here's how.

Millions watched Floyd Mayweather defeat Conor McGregor by TKO Saturday night, and some of them may have been caught red-handed viewing illegal broadcasts.

TorrentFreak, a copyright and file sharing news site, received reports that a watermark was embedded into streams originating from the Sky Sports Box Office broadcast. The watermark, which appeared as a series of numbers and letters, could have been used to track people watching the illegal streams.

"It’s certainly possible that the sequence of numbers would allow Sky to track the illicit stream back to a subscriber and/or a set-top box tied to a particular account,” wrote TorrentFreak. “Since that subscriber has then re-streamed that content back online illegally, the code would act as a homing beacon and could spell bad news for the individual involved.”

So, if you were one of the millions of people watching the fight without paying the $99 pay-per-view bill, and you saw some strange code flash on the screen, you might be in some trouble. Or, you could be fine. TorrentFreak left open the possibility that the watermark was placed by the illicit streamer to track the stream and prevent it from being 'stolen.'

Despite preemptive efforts by Showtime and Sky Box Office to shut down sites that host illegal streams, the streamers are still ahead of the curve. For example, large numbers of people used social media, such as Facebook Live or Periscope, to broadcast the fight free of charge to others.

Some viewers may have had a valid excuse for pirating the broadcast. The official live stream suffered from technical issues that actually delayed the start time of the fight by about an hour. You can't expect viewers who paid nearly $100 for a fight to just sit back and do nothing when their cable or internet provider fails them.

The official number of pay-per-view purchases has not been released, but estimates before the fight indicated that the number could exceed 5 million. Variety has reported that 2.9 million viewers watched illegal live streams. That's a lot of money lost to piracy, but neither Mayweather nor McGregor is hurting for cash. Between the fight purse and their cut of promotional money, both men likely took home $100 million or more.

And let's not shed any tears for the networks, either. Despite all the piracy, the event is estimated to bring in a record $1 billion in revenue.