Well neither the psychology of the individual nor that of markets allows constraints defined by economic theory of rational agents.
Say, I've been meaning to report to one of your Biker reports that I've encountered a couple multi-taskers in MD: phoning while pedaling. Is this the seed of a trend? I hope not. Diversity is the key to economic and political evolution.
But ... I don't call those gadgets to allow people to use the mobile in the car "hands free mobiles" ... I call them "brain free driving".
At least if the cyclist is doing it, they are mostly risking their own neck. I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.