Oddly enough, in stuffy industries not adhering to the dress code is a strong social signal that you're good enough to be able to flaunt it.
This is classic countersignalling behaviour: By refusing to pay the cost (financial, time, and comfort) of dressing up, you're communicating that you're not afraid of being mistaken for an interloper.
permanent 3-day stubble
I really want to know how to do this. My stubble goes from 0-day to 1-day to 2-day to 3-day and then back to 0-day...