Careful with that one. Free and Appropriate Public Education comes to mind. Normally, administrators remove people from programs for various reasons which make it legally ok. You kicking them out of the program altogether may break that law. I would be wary of an administator who also put me in the position to "make this decision." Even lowering a student of their office in the band or any kind of punishment will need advice from people who get paid more than you. Least restrictive environment also comes to mind. Tread carefully. See if you can find a positive way to wrap up the incident.