What if the player is deaf?

I'm sure if kept at a reasonable decible level, you could hear the shrill of any fire alarm. Either way, the panicked outcry and subsequent stampede of the fleeing crowd should clue any reasonable person in.
Besides, if that were the case, we wouldn't be allowed to wear them inside
any building.
My Sony mp3 is tiny and fits in my pants pocket. Then I usually run the cords under my shirt, but even when I don't, people have said they didn't even notice I was wearing it.
I think as long as it remains inconspicuous, it should be allowed.