It doesn't change lanes when it knows it's changing lanes. If the Tesla thought it was staying in the correct lane, it wouldn't ask for the confirmation.
This discussion is under a nonsense test report and headline btw. The car was moving slowly, around what could easily be identified by gps and vision as some sort of test track or empty lot, with varied and inconsistent markings and no other traffic in sight.
The software running on drivers has been under active development for much longer than Tesla. (I'd start bidding at billions of years, though I'm willing to get argued down to tens of thousands.)