Missouri State MT April 1 decision???

Hey all you knowledge people. Quick question about Missouri State MT. My niece has been accepted academically and artistically, however, she was notified today she had to make a decision by 4/1 or lose her spot. What’s up with that? Thought National College Decision Day was May 1? She still has an audition 4/30 at UCF and is still waiting on 5-6 decisions and aid packages. Can they really do that?