I took a professor for book of mormon at BYU, his name was Alan Parrish. He was a huge guy, maybe 6'8'' with mitts as hands. Anyway, he told a group of us that when he went to high school he chose to play at Utah state instead of BYU, because back then BYU wouldn't let their basketball players go on missions, whenever they wanted to the GA would come talk to them and convince them not to.
However, obviously he doesn't harbor any anger against BYU since he has taught there for like 20 years. He says this kind of thing doesn't happen anymore, but said that in the 70's when he played going on a mission was highly frowned upon.