I'm not convinced on their advice. If you try opening your car *without* the key nearby, you can hear the high-pitched whistle as the car polls for the key.

As a programmer, with the fact that the car has more power than the key, this is the way I'd code it - user attempts to unlock car by touching handle or trunk button, check for key, if key found - unlock and wake, otherwise revert to sleep mode.

There is no logical reason for the car to poll for the key UNLESS you're asking it to do something - like start, lock, or unlock. I did read somewhere about the 2012 models lighting up as you walk towards them, which would be illogical as it'd require frequent key polling (battery drain) but prior models certainly don't do that.

All I can surmise is that locking the car demands the car enter "sleep" immediately (powers down cabin lights, A/C, radio if left on etc etc) rather than waiting for the timeout.