Also ran at a UAA school. Typically, once you were on the team, you stayed unless you had behavioral issues or serious work ethic problems. That does not mean that anyone could get on the team, however. There were recruiting standards. You had to be good in high school or have a great tryout to get on the team because our coaching staff was under serious pressure from the administration to keep the team numbers down. The school straight up told my coach that they would not fund a roster over 35 male athletes, so the 36th guy wouldn't go to any meets. So it was a big roster, but not exactly all comers. Certainly not required to take everyone that showed up.