How is it an excuse. Because a band director runs his program how he wants...yeah, okHere comes that express themselves crap. I hear parents use that excuse daily.
Heck, when I played baseball at FAMU, we weren't allowed to have beards or sideburns and growing up my dad wouldn't allow me to have dreads or braids...if the rule is there, then I'll comply and I'd tell my children to comply. If the rule isn't there, then EXPRESS YOURSELF however you want