Walking and Talking

From the "Why Would Anyone Think Of That?" file:

Researchers at the VTT Technical Research Centre of Finland have developed a prototype of a cell phone that uses motion sensors to record a user's walking pattern of movement, or gait. The device then periodically checks to see that it is still in the possession of its legitimate owner, by measuring the current stride and comparing it against that stored in its memory.

Some limitations, tho':

wearing high heels, suffering an injury foot and, especially, having a few drinks, are activities likely to set the device off by accident. "You would need to either turn it off before you start drinking or make sure you remember your password"

And if you wear high heels, suffer a foot injury, and have a few drinks all at the same time, the thing may just explode.