[icebraining]

And the user can manually force a lock, from the watch, overriding the proximity/signal strength. To intercept this the attacker would need to decipher the messages.

Not if the attacker stops the relay right after the PC is unlocked.

[rrebelo]

> Not if the attacker stops the relay right after the PC is unlocked.

No, if it happens the program falls back into the "user is away->lock the computer" mode.

[icebraining]

So what happens if my watch shuts down for some reason while I'm using the computer?