Perhaps BYU should just increase tuition by proposed $100 - $150 and just offer all the students an athletic pass card. They don't line item the cost.
BTW - You also proved my point. You're right that I choose to pay tithing (even though I'm commanded to do it.) BYU could easily add the cost to the tuition fees and GIVE the students an athletic access card as part of the "BYU experience." The students don't get to decide how the $$ are distributed. Students who "choose" to attend BYU would pay the tuition amount. Sounds a lot like what I'm doing.