You know it's true, right?
It doesn't matter what your company's dress code is. People naturally filter in a type of caste system when it comes to how they dress. You can identify the type of employee by what they wear. Here's a taste of that from a former intern at a tech startup via TechCrunch:
"When the doors opened onto the third floor I had my first introduction to the startup dress code. If you’ve worked for a startup before, you know the code I’m talking about. It allows you to subconsciously identify someone’s role at a company just by what they wear. I won’t give away all the details, but it’s usually something like this:
developers have some variation of the Zuckerberg hoodie,
designers have some sort of bright-colored shoes,
the business guys wear collared shirts, and;
the venture capitalists wear sweaters over a collared shirt.
I fit into none of these categories that day, and stuck out like a sore thumb. Classic intern.
So it's not your formal dress code that matters. It's the informal one.
If you want a great marketing opportunity to make you look human in HR, have fun with the informal dress code. Fashion show? Sure... Career site parodies? Absolutely. I think some type of "natural habitat" feature is a great way to parody the tribe-based dress code in your company.
Make fun of the tribes and how they dress in a nice way. Everyone will wink and nod, and you'll look smart.