What % of high school athletics takes place on Sunday? I would estimate it to be very low, like less than 5% of all possible games (since we're not just talking about football).
I genuinely don't know, that's why I'm asking. To me, it seems like a rare exception for the HS game to be played on Sunday, and even more rare for a BYU coach to happen to be attending.
That's going out on some pretty thin limbs in order to try and shift the paradigm.