For starters you could put the unit in pause mode with the 'off' visual (is it a visual when the display is blanked?).
I do this by routine when I let the empeg sit in the car. I had it turn on once by itself and don't know what caused it, so if it decides to do this again I'm certain it won't start playing loud music and doesn't show it's fancy face (uhm, display) to attract nasty people. Don't worry, I only let the empeg sit in the car if I'm back in 15 minutes or less. Most of the time this happens when I stop at home for a quick meal with the car parked under the car port next to a big window.