I was under the impression that when the Hold Assist function came in to use the rear brake light would stay on thus shinning in the face of the driver behind. I mentioned this to my dealer this morning and he said that was not the case. When hold assist engages the rear brake lights go out. So we went outside and he started up a car with the Hold Assist option, switched it on and applied the brake. As soon as he took his foot of the brake pedal the brake lights went out and as it was an s-tronic there was no tendency for to creep forward.