won 4 out of the previous 5 head-to-head matchups. Also, Utah and BYU were competing for more of the same recruits then. As such, at least part of the motivation was to avoid BYU because of the potential for a loss which could then hurt recruiting.
Of course, in retrospect, that seems silly now because of Utah's winning streak and the fact that they don't fight over as many recruits these days as they used to.
It was a die-hard Ute fan who first told me the above hypothesis, I didn't come up with it myself.