yeah, I'd say speed is the difference, as you noted. That happy family has nothing to worry about. That bike racer will get road rash if he goes down, no doubt, but he's still not doing the kind of speed which you attain on a motorbike. That kind of road rash very well may land you in a burn unit for treatment. We're talking apples and oranges CDNSushi.

In case there haven't been enough dissenting opinions, I'll add mine. don't do it. Risk doesn't outweigh the benefits in my opinion. And yes, I ride, and it's ATGATT for me thanks (All The Gear, All The Time!)