Just noticed something that I believe is not intended behavior. Me and my daughter was in the middle of our daily wrestle match, when I decided to check her pulse through the complication. Removing the watch from my wrist I had to input my passcode to get to the complication on her wrist. But when I got a reading of her pulse and then removed the watch it did not lock and I could place it on my wrist without having to input my code. In short you can in theory remove someone's watch and put it on your arm and access everything. But then again if someone managed doing all that they deserve my watch.