I was in the clink for a while, so this may be old news to some. There never was or will be a QB controversy with Hill and Stewart. Hill is the superior QB. Like Bronco said, Stewart will only play if Taysom is banged up or the score is lopsided.
I think this tips BYU's hand and shows us part of what BYU's offensive strategy is this year. It shows that Anae and Co. are giving Taysom free reign to run and aren't going to hold him back. They are okay with him running with reckless abandon although they will advise him to "be careful/smart". They are aware this is a risky strategy and this is why Stewart is getting a lot of reps.
It's that easy...