Jill toys with the idea of wearing a bunad -- a garmet that seems to occupy, in Norway, the psychic niche that Scots reserve for the kilt -- to her defense. (Read Elin's comment, too, for essential background)
The notion that clothes carry ideas more subtle than "I am rich, or pretty, or popular" is novel to me, but Anne Hollander's delightful Feeding The Eye is full of them. Of particular note is her essay on the Japanese kimono, a dress style I thought went back through the ages but that actually is only a few decades old. Hollander does a fascinating job exploring why the kimono is a living garment in the way the kilt is not. Even better, her essay on Chanel explores the ideological and political motivations behind the little black dress.
Fussell, in The Boy's Crusade, refers to the American soldier's novel sloppery, the lounging, casual attitude in dress and posture that puzzled and delighted a Europe in 1944-5 that expected soldiers to look and act like Prussians.