Apple Watch will get Activation Lock with watchOS 2
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Activation Lock has been available on iPhones and iPads since the release of iOS 7 and has caused a pretty significant drop in Apple device theft over the course of a year post-launch. The service will automatically lock an iPhone and bar any access to it, if thieves attempt to reset it without having the owner's iCloud credentials.
Well, with watchOS 2, the same service will be available for the Apple Watch – should the device detect malicious intent, it will lock itself and become a metal-and-glass paperweight unless it receives the proper iCloud username and password. Of course, we wouldn't wish anyone to ever need said feature.
source: Apple
Things that are NOT allowed: