Watching
the vid, it clearly tracks the solid line until the driver brakes...
In real life on this side of the pond I've seen drivers go straight into the divider without help from an 'autopilot' simply because they've not been paying attention
And that I suspect is the case.... and what Tesla should look at, rather than calling it an 'autopilot' they should call it a driver assist and ensure that all drivers of cars equipped with it are reminded that it does'nt absolve you of the responsibility of actually driving the thing
adding a warning bell with a loud voice saying "WARNING: DRIVE ASSIST WILL DISENGAGE" would help, along with a pair of dead man switches on the back of the steering wheel so you keep your hands on the wheel at all times....... mind you the last would help every other car driver too...