Jeff Benjamin, writing for iDownloadBlog:
The Apple Watch contains security measures to prevent thieves from accessing your data, but it doesn’t include the necessary features to dissuade thieves from trying to steal your device to begin with.
The problem stems from the lack of an Activation Lock-like feature on Watch OS 1.0.
Unlike the iPhone, if someone steals your Apple Watch, they can easily reset the device (bypass the passcode), and pair it with a new iPhone logged in to a different iCloud account. In other words, it’s totally feasible to steal an Apple Watch and set it up on a different device as if you just purchased it from an Apple Store.
Caveat emptor. Know, going into this transaction, that there is no Find My Apple Watch and there is no Erase My Apple Watch. The good news is that your data is protected. It either lives on your iPhone and won’t disappear if someone takes your watch, or it is protected by a passcode lock, should you choose to enable one:
The positive spin that we can put on this is that the Apple Watch does protect your data. If you have a passcode lock on the device, which we wholeheartedly recommend, at least it will prevent the thief from accessing your personal data on the device.
It will be interesting to see if Apple ultimately adds in an Activation Lock feature for future versions of Apple Watch. I suspect this will become more likely if we start seeing a wave of Apple Watch thefts.