People have made the very reasonable argument that in a multi-billion dollar industry (sports) that depends to a certain degree on "judgment calls" that there HAS to be a less than insignificant level of "cheating" by officials.
We see cheating in every other aspect, but we refuse sometimes to acknowledge its possibility by officials. Even after a ref or two comes out to and comments that it happens. I think that we convince ourselves to believe it is not true because we love to watch the games. If we were to discuss and even possibly accept that the playing field may not be equal it would fundamentally undermine something EVERYONE on here loves (sports). We won't allow ourselves to believe it is possible.
With that said, it is also very difficult to prove. This video (from Reddit, yes) is pretty interesting:
What do you think?