If you’re like us, you’ll probably want to show off your Glass to some of your friends and family, but you don’t necessarily want them sending messages or making phone calls on your behalf. To safeguard your Glass when others are playing with it, turn on Guest mode from the Settings bundle.
Guest mode will show an example timeline, complete with Google Now cards, a few sample emails, and a few other cards designed to demonstrate the device. Your guests can still take photos and videos, but they can't be shared outside of your device. When you turn off Guest Mode, all changes, messages, and other timeline items are erased except for searches, pictures, and videos. Search history, pictures, and video are saved to your timeline so you can share them with your friend later as a memento of their Glass experience.
Turn off guest mode by returning to settings and tapping the Guest Mode card.