You are exactly right. They should be hydrating before, during and after practice. They should notify someone if they’re feeling poorly. If they don’t feel comfortable starting yet because they’re not prepared, they should not participate except on a limited basis. Even then these tragedies may occur though. Prayers to the family. I have had my teen athletes working out separately this entire time. Running, lifting, agilities, etc. They are all in good shape. I have no fear of them participating.