I thought the same thing you did, until I thought a little bit more about why those door locks work the way they do.
No car company can really stop people from locking their keys in their cars without fancy solutions like RFID fingers or Bluetooth or some-such. I don't think the people at Isuzu who designed your car door thought that they could. Instead, they were trying to solve the problem of unintentionally closing the locked door. It seems like something that doesn't happen often, but what if you had locked the door, then went for something you had tossed on the roof, etc., then bumped the door shut? Maybe the wind blew? Holding the door handle isn't supposed to make you think about your keys, it's only supposed to confirm that it's a human performing the action. Wind doesn't hold door handles open.
Of course, this doesn't really relate to your UAC analogy. Sorry.