Whether referring to bettors or odds makers, people are usually making an appeal to authority of a group opinion.

In the case of bettors, people are using it because it sounds better than posting, “50% of sports betters don’t think BYU will win.” (A more accurate but admittedly, weird statement. I doubt we’ll see anyone post that even though it’s what a -1.5 pt spread means.)

At -1.5, bettors just have to pick who they think will win the game. Since the spread is designed to encourage even betting, by definition ~50% think BYU will win ~50% think BYU will lose. I suppose there could be a few counting on that 1-point BYU loss going in their favor, but that can’t be a statistically significant group. A bigger spread would definitely have some counting on a closer loss.)

If the spread moves towards Arizona, it means the betting was uneven with more betting on Arizona. If the spread moves towards BYU, more were picking BYU. Even then, it’s about even money, so it could be fewer people betting one way, but larger wagers could be the cause of the uneven betting.

In the case of odds makers, people erroneously use it to say odds makers don’t believe in BYU or if we’re favored to say they go. By definition, it’s odds makers best guess as to a number that will result in 1/2 of betters going one way or the other. It has nothing to do with what oddsmakers believe will be the outcome of the game.

Getting to your aside…

Other factors certainly come into play as well.

For example, if BYU’s fan base may bet less than an opposing fan base, that could skew the opening line. Or if you have a disproportionately large fanbase, like a ND, Texas, Alabama, etc. It could be that a certain team has become a favorite of bettors. (Think of Colorado with Deion. I would guess their extra interest has affected their lines.) All of those things would affect where the spread is set and then the odds makers will make adjustments based on how the bets come in.

So it’s very possible that our spreads are being affected by very few BYU fans participating in the BYU side of the betting compared to opponents. As BYU consistently beats the spread, that may change as more fans begin to participate or unaffiliated bettors become attracted to BYU lines. (Think of Iowa scoring the last few lines. As they hit the under so consistently they began to attract a lot of extra betting attention the last few years.)

So, yes, bettor perception will affect the opening spread, but that spread will be affected by factors such as participation in addition to certain perceptions.

I’ll try to chime in less on this topic moving forward.