Those are really neat, but as mentioned before, I wouldn't listen to music on the slopes for exactly that reason. There have been numerous instances when I was able to hear someone bombing down the hill a couple seconds before I saw them...saved my butt more than once!
Although if it was a prettly slow day with empty runs, I can see where listening to music might be nice. Then again, I love the sound of the edge slicing through the slope.
To each his own! Just be safe :)