Prayer in public school sports

I have witnessed several different public school athletic teams praying either before or after competitions. They did it as a group and one of the prayers, the most recent, was in a crowded, noisy gymnasium before a competition.
There were not coaches around or involved; it seemed, to me, like an act undertaken by the athletes, and they all seemed willing participants.
My question is whether it should be allowed? Is it the right of those students to exercise their religious freedom and ask for a heavenly blessing before, during or after competitions? Or are the actions of those students impinging on the rights of students who either don’t want to pray or are of a different faith? Would students be brave enough to tell their teammates they don’t want to pray? Or would they feel pressured to participate because they want to be part of the team?
Is it okay if everyone on the team is of the same faith? What if the team members discuss it and decide that’s what they want to do?
And finally, how should a coach or principal handle this situation if they hear about it or happen upon it?