I find this a bit strange. I think more devices would probably be stolen by setting the device down, or putting it in your bag and it getting snatched, rather than someone pulling it off your head. And unnatural movement is pretty hard to define.
Seems like it would be better to just be able to remotely lock them if you know its been stolen than them locking automatically.
You're right, for sure. It seems like a less likely scenario. That being said, the abstract at the bottom of the article makes it sound like the patent involves profiling your normal movement patterns and then using that to determine if the glasses are being worn by someone else. If that's the case, and it actually works, then this might actually cover pretty a broad range of thefts. Anyone had a chance to read the patent yet?
Edit: Thinking more about it, I don't think that could work. Even assuming people had identifiable walking patterns, there's always going to be things that unexpectedly change that (e.g. injury, or heavy bags while shopping).
Depending on how you interact with Google Glass, it could simply make sure that your hand is yours, or that your eye is yours, and not allow anyone else to use the device (unless you put it in a "guest" mode for X amount of time.)
They will want "unnatural movement" to be hard to closely define so the patent covers as much territory as possible. The specific detection will be work in progress.
Seems like it would be better to just be able to remotely lock them if you know its been stolen than them locking automatically.