The Court of Appeal has ruled on Phillip John Smith's right to wear a wig in prison, finding that it doesn't engage the protections of the right to freedom of expression affirmed in the Bill of Rights Act. Reading the judgement, its a bit more complicated than that: technically they find the appeal moot, because Corrections has given Smith his wig back, and formally declined to answer the question - but said that that's how they would rule if they had to. Digging down, its essentially because they think wearing the wig wasn't an attempt to convey meaning to another (at 46) or because it attempted to convey normality rather than difference (at 51). Because obviously, being "normal" doesn't mean anything. Meanwhile, if you ask a person on the street what a bald man wearing a wig expresses, they will tell you quite clearly: insecurity. And beyond that, a desire to be seen as young, virile, whatever.
This part of the judgement misses the obvious: that even in what we think of as an informal society, we have elaborate codes of dress telling us what our clothes, hair, makeup and appearance in general express (even if its "fuck all that fashion shit"). If you look at someone, you make judgements based on their clothing and appearance, and people seek to manipulate these judgements by changing how they look. If I wear a suit to a job interview, I communicate one thing, if I wear combats and a hoodie instead, I communicate another. And only a moron (or a Court of Appeal Judge) would think that I wasn't trying to communicate information by how I chose to look. The judicial system is on-record as thinking disco-pants in court communicate something inappropriate, and you can bet that if I turned up in the Court of Appeal and just sat there wearing a parody judge outfit, with robes, a wig, and drunk-face makeup, the judge would damn well think I was expressing something (contempt, probably).
More generally, how we choose to appear is one of our most basic forms of day-to-day expression. Appearance expresses to ourselves and others who we are, who we want to be, and how we want to be seen. That's why they seek to control it in prisons, schools, the military, and other conformist institutions such as the law. I'm not going to pretend that its high-falutin' Milton poetry or something a member of our snobbish judiciary would think is socially valuable, but to pretend it is devoid of expressive content and conveys nothing to others is a form of social blindness I'd expect only from aliens.