I think BYU fans may believe that most people understand that issue because it is part of your values. Sometimes when something is so common to you (you as in you in general, not BYU fans), you forget that it may not be as common to others and you just expect people to get it. I truly believe that many of you (and I'm not insulting you) feel that most people just understand BYU doesn't play on Sundays. I don't believe those not familiar with BYU and the Mormon church understand how important it is to you. I think many understand BYU doesn't like to play on sunday, but for the right amount of "Money" or "Access" or whatever you want to put in "____", BYU would be willing to budge on that issue.
When I was a little boy and my father was alive, I remember going fishing with him ever Sunday morning in the spring, summer and fall. That was our thing! I would always invite my friend, but he would never go. I always thought it was because he had church in the morning so he couldn't. I didn't understand until later in life, and many invites for different things that I understood that it was a Sunday issue, not a church issue. It wasn't really until one year when the Yankees were in the World Series playing on a Sunday night and I had tickets and invited him to go with me (and he didn't) that I understood it was a Sunday thing, not a Church thing.
I guess my point is that I wouldn't just suspect that many not of the Mormon faith understand how important Sunday play is an issue to you. I think many believe that just the opportunity to be in the PAC12 or Big12 is reason enough to compromise that standard.