I think if the schedules conflict on a regular basis, the cheerleader needs to make a decision to drop one. It is not fair to either team to have someone with a re-occuring schedule conflict. I am sure there are other girls who would love to take her place who does not have a schedule conflict (on either the high school team or all-star team).
I will say that we have a few girls who do both all-star and rec. I overheard a conversation between parents on which team the parent gave priority to. The mom said both are "equally" important to her. She is actively involved in both organizations. I see her point of view as she is involved in both, but I also know the cost difference between rec and all-stars. Just because they are both "equally" important to her, doesn't mean they are both equally important to me and the rest of the team. I pay a lot of money for my daughter to do all-star cheer and if her daughter is absent for rec (which hasn't happened yet), I would not be happy. It doesn't just effect that one child with the schedule conflict, it affects the entire team. Some kids/parents are making huge sacrafices to have their kids on all-star teams and to have a team member with constant schedule issues is not fair to them.
It's great if the schedules work out and don't conflict, but if they do, they do, and decisions need to be made for the best interest of both teams and all girls involved.