iPad disabled for 15 mins on its own after iTunes started playing

I was sleeping and my tablet was on my nightstand (nothing near it to push any buttons. I woke up to my iTunes playing by itself around 1:15am. I unlocked the screen, shut iTunes off, and closed anything that was open in the background. I just got back to sleep and 15 minutes later iTunes started playing a different song. I picked it back up to shut iTunes down again, and this time the iPad was disabled for 15 minutes (no one or nothing around to have tried my passcode). I did a hard shutdown and when it came back up it said only disabled for 5 more mins? I waited, unlocked it and nothing was open? What can cause this?