I've recently obtained an iPod and a radio adapter so I can play it in my car. the iPod stores music, the radio adapter transmits the music into radio waves, and the radio plays the music.
1: most radio antennae, unless very specially designed, can function equally well as transmitters or recievers.
The radio adapter on the iPod is cheap to buy, and likely uses an off-the-shelf antenna, suitable for transmission, or reception.
2: Plugging the radio adapter into the iPod, or into a power source, or disconnecting it from a power source causes the screen to light up (it powers up whenever the device senses a change in power sources.)
3: Plugging the ipod into any power source, or disconnecting it from any power source causes it to power up and play.
4: The data on the iPod can be accessed either by playing the music, or copying it digitally. The files on the iPod can be accessed digitally as if they were any file on any removable storage media.
5: The iPod has one data port, which can be used to connect it to either a computer, a docking port for playing music, or the radio adapter.
Based on these facts, I believe it would be possible to design a device for music pirates (ARR!) to hijack (AYE!) the music from iPods attached to radio adapters. I shall refer to this hypothetical devices as the Music Hijacker, and undoubtedly, some evil scientist is currently making such a device, shaped somewhat like a toy pirate ship.
The Music Hijacker will NOT comply with FCC regulations. Instead, it will transmit "interference" in the form of a powerful signal, simulating connection to, or disconnection from a 12 volt power source of 1.5 amps or less. Due to FCC regulations, the radio adapter will be forced to accept this intereference, mistaking it for an actual power source, thereby powering up itself, and incidentally, the iPod.
the iPod will then power up, and begin playing, and the music will be transmitted via the radio adapter until it's batteries run out, or until someone tells it to do something else.
Once playing, the music Hijacker can record the now playing music. Alternately, it might be possible to simulate a computer attempting to copy the music files from the iPod into the computer, making it possible to rapidly hijack all the music from the iPod.