he was frustrated with the sprinklers running on gameday on more than one occasion and even voiced his frustrations about it to someone (AD, ground crew?? I'm not sure who). I think he was mentioning this about the TCU games perhaps?
The point is, that this sort of tactic would affect both teams equally and even IF it was happening, I'm not convinced it had anything to do with some sort of plot to give BYU an advantage and may have been more simply some sort of weird watering schedule by the grounds crew.