Over the last few days I've been noticing when I put my watch back on in the morning I would forget to enter the pass code, but after around 30 mins the watch was unlocked! I was wondering what this could be; was it measuring my heart beat and deciding it was me, or ha a picture of my wrist? No, it turns out if you put your watch on and then unlock your iPhone it unlocks your watch...! Didn't know this, handy as don't have to worry about pressing the small numbers with my giant fingers, but cant help to think there may be some security loophole there maybe? I.e. someone mugs you for your watch, it locks, they put it on their wrist then you go to call the police and your watch is now unlocked!