My school has a strict uniform policy. That email was professional and to the point. It was nothing unprofessional about it. The uniform policy was taught and discussed in an earlier class. When you are in uniform you should take pride in it, you should be professional and represent the school and yourself at all times. If you think that email was unprofessional well I seriously think you need to rethink your profession. Listen, follow the rules and procedures and don't sweat the small stuff.