[snowbrook]

I don't see how it can distinguish between normal use of your hand/arm and a control gesture. Perhaps in the midst of a video game, you are gesturing full-time, but the other examples seem more dubious to me.

[27182818284]

It has a special unlock gesture like your phone.

[pm90]

That's a good point. Maybe you would have to do a particular gesture to get it "live"? But I'm just speculating here

[vicbrooker]

I remember reading that they've selected a gesture that isn't likely to happen naturally to enable or disable the device.