Speaking as someone who has gone down on a 10 speed bike (gear chain came off bike and locked the front wheel up and I wasn't wearing a helmet), I can only imagine what a much heavier machine with hot pipes would do as well as the higher speeds and force of impact on the ground. 10 speed damage was NOT fun (what little I remember of it since I blacked out a few times). I had road rash from my left forehead, down my face, down my neck, on my collar bone and shoulder, and on my hands and wrists, one wrist took the impact weird and I had to have chiropractic treatment to get it working smoothly again. I don't know how long I skidded on my face/head -- I pretty much instantly hit like that and slid for a while. I was going slightly down hill and trying to speed up to catch up with someone -- no idea how fast. I no longer ride a bicycle without a helmet due to that scare -- I was very lucky I didn't mess myself up worse.

If I rode a motorcycle (I have considered it off and on over the years), I would definitely be wearing full safety equipment all over as csbdr said.

I think most people aren't replying with helpful replies because they simply won't do it and don't want to encourage it. Plus, there is the issue of how to keep clothing down and keep modesty, not to mention safety hazards of anything hanging, flapping, getting in the way or distracting the rider. I definitely would not recommend regimental, you might find yourself getting into more trouble than just road rash if you get my drift.