i've never been. more then 400 bux to get in to something you have to bring everything yourself and take it back again and can't even get there without owning a vehicule or bumming a ride with someone who does is a bit beyond me. i've seen lots of pictures. every year i look for pictures and videos people post afterwords. because there is a lot of creativity and imagination and that's what interests me. and so, judging by the pictures, a lot of people do run around half naked, but we're talking about a desert climate, where i sort of think this isn't really all that good of an idea because dehydration can become a serious health issue. that and of course radiation burns from the sun.
I've never been to burning man but I've definitely heard of it. As for clothing optional, I think there are some common sense boundaries. Girls have to keep their nipples in check (thus, pasties) and that sort of thing. However I have seen pictures to the contrary...
I live in the land of sanctimonious burners. Clothes are optional. Costumes, it seems, are not. But lots of skin and bits on view is rather standard. (According to my neighbors)
I reckon they should have a burn a packet of cornflakes ceremony. Cornflakes were the original "health food" bit nothing healthy about them. It also heralded the start of the processed food industry.