Rest PIN or reset PIN? You should have enabled a PIN on your watch to prevent anyone from getting at your personal data while it's off your wrist or while you are sleeping. If you set a security PIN for the watch, you will need that PIN, should you need to ever reset your watch - this, too, is to prevent someone other than you from resetting your watch. If you have not set up an unlock PIN on your watch, you likely will have to set up a reset PIN, for the reasons stated above. This may be a new feature they added.
