What is AT P&N's thoughts on this ingenious rational?
Sounds about right, on the face of it. However, context is important and none has been provided here.
I've seen my share of stupid school policies, such as suspending a boy from school because he had a Batman symbol shaved on the back of his head, or that it should even be a debatable question that girls should be allowed to wear trousers rather than standard uniform skirts/dresses on cold/windy days, yet some schools run idiotic policies.
As with a lot of things, kids try to push the boundaries of what they perceive as acceptable behaviour. The more that authority tries to enforce 'acceptable behaviour', the more the kids will push, especially if the rules are stupid. Girls have to jump through a lot more hoops in this respect than boys do, at least in my experience, so it's no surprise that they're going to rebel. So, if an organisation such as a school has rules such as what constitutes acceptable attire, they should bear in mind that their rules should actually be for sensible reasons that most sensible people won't bother to debate, rather than trying to enforce a stupid policy based on their utopian (and/or puritan) mental picture of how teenagers are going to look and behave.
If having a short skirt is no longer a sign of rebellion, then is it worth the aggravation (of say a windy/cold day)?