Apple - iTunes keeps opening on its own
WOW I finally figured this out.
Tampering with the audio jack will cause this to happen. I have headphones with the play/pause/skip control button, so the issue might not show up with standard headphones. If I tap (or double tap) the headphones where it is connected to the jack, the effect is the same as if I clicked the remote button that was designed to control playback.
What's happening is my movement is jarring the headphones and even a very slight tug will open iTunes and start playing music. Very frustrating when I'm using my headset for a phone call!