Have you done one? I see there was one in Chicago, and Portland. Big one in London. I wonder how they got around the public decency laws, at least I thought there was one to prevent indecent exposure. Also would think it's uncomfortable.
I will be participating in this years Philly naked bike ride, yes. I been wanting to for a few years but something always came up, but not this year! Public nudity is protected freedom of expression within the context of a protest. The wnbr is a world wide protest for bike advocacy/safty and alternate forms of energy. I have friends that do it every year, they always tell me how much fun they have and how great all the people involved are, i cant wait to do it this summer. And to answer your last question, no, mountain biking naked is actually VERY comfortable. Just dont fall lol : )
Ps. Being nude is not required to participate, try one out you will probably love it.
I was at a wedding reception at some kind of summer resort and they had some loaner bikes for the guests in various states of disrepair. I got a report in the morning that apparently I was seen riding a tireless bike in the buff while racing a couple of cousins who were also nude on a tandem.
I don't know if I was comfortable, but my knee was pretty skinned up the next day and I had a wicked hangover.