If your "geeks" can't figure out proper attire for the office, perhaps you don't need them as badly as you think. Such behavior indicates a lack of engagement with the workforce which can (and does in my experience) translate before long into interminable personnel issues and complaints.
Businesses don't need to coddle. Geeks are two-a-penny, there's always a fresh batch cooking in the halls of "learning" and I've yet to see any business collapse when their coddled geek du jour decided he was better than them and packed his bags for pastures new.
In the words of Sherman Potter to Charles Winchester: *No-one* is that good.