But let's play by your set of rules. What would be something nobody but a coder would wear?
Bonus question. If "clothing is signalling", what does a typical coder's outfit say about their ability to come up with non copy-paste solutions?
Double bonus question. What do you think of black coders, who are even less common than female coders? Do you presume they are at a tech event to play basketball? Would you advise them to come in white face so they could provide the right "signalling"?
Also, let's get the numbers straight. Women comprise about 30% of computing workforce, a far cry from 5% that you made up to justify sexist stereotyping: http://en.wikipedia.org/wiki/Women_in_computing#Statistics_i...).