Of course not. That is horrible and avery dumb thing to do.
It puts yourself and others in danger. Once last summer I was on a climb and wanted to pass someone and yelled on your left...he was totally startled...he was wearing an ipod. I was shocked as I didnt believe anyone could be so stupid as to wear one, then I noticed the odd one here and there.
Curious: if you were in an accident wearing one, where would the blame fall? I know you THINK you can hear everything but its hard enough without them. Maybe not the politest way to say it but when I see someone riding with music do judge them, and think they are a jackass...but these are the people that wear ipods to running races when that is prohibited too. (not to open another can of worms!)