remark about smugness retracted here. When I made it I was thinking of a particular incident when a rather large rider passed me on what my husband pointed out was a P.O.S. bike and then proceeded to disappear down the trail with his hands resting behind his head(after passing several other riders). His body language seemd to say, "look, I'm a big guy on a P.O.S. bike and I'm mopping the floor with all of you!" I was thinking "you GO, big guy!" at the time, so my asessment of smugness isn't necessarily a bad thing...

I'm glad to learn that there are also useful reasons why one would ride hands free.