Books, Bikes, Boomsticks | Tam | About time...Amen!
Seriously, if a plane's electronics are so temperamental that they're in danger of going all divide-by-zero should somebody accidentally turn on their mp3 player at the wrong moment, are you sure that it deserves an airworthiness certificate?
You know how I know that electronics aren't dangerous for planes? If they were actually dangerous, there's no way they would be allowed in the cabin in the first place. If there was a real danger, then the procedure for eliminating that danger would not consist entirely of "have the bored flight attendants wander the aisle and do a cursory visual check for people wearing headphones."
New strategy for terrorists: stop trying to sneak bombs/guns/knives/letter openers/nail clippers onto planes, and just fly with a bag full of cell phones and laptops and mp3 players and GPS receivers. (And a Discman, but only for hipster terrorists who are into the whole retro thing.) Sooner or later your plane will fall out of the sky. I know this is true because the FAA tells me so.