I don't understand the central locking?

[scott]

I unlocked my car earlier to get something out, I then obviously forgot to lock it again and then went in to London leaving my car at home. I got back (it was dark) and noticed the red light wasn't flashing and car was unlocked, clearly remembering I didn't lock it, now what I don't under stand is I can unlock the car and put the key on the windscreen out side and after about 30 seconds it will lock itself?? Would it not be a good idea to lock itself when the key is faraway/undetected or been left unlocked for a certain time??? Rather than when the are nearby??

 

[timmus]

Your car has no idea if the key is nearby or not.

If you unlock the car and open one of the doors, then you have to lock it again. It won't 'auto-lock' if one of the doors has been opened, as this raises the possibility of you opening the door, putting your keys inside, and then having them locked inside the car.
If, however, you unlock the car and then don't open any of the doors, it will lock itself after 30 seconds, as it concludes that you got distratced, or that the button was accidentally pressed.

Tom