Stop the press! The lightbar on the top of the DualShock 4 controller does not turn off! The news comes directly from Sony Computer Entertainment Worldwide Studios president Shuhei Yoshida who confirmed it via Twitter over the weekend.
The original question seemed to stem from concern that the lightbar would drain the DualShock 4's battery quicker. However, concern has since grown over the lighbar's possible reflection in glossy TV screens. There's worry that when playing a game in a dark room, the light would reflect off of a glossy screen, ruining any sense of immersion.
Admittedly, this really seemed like a non-issue at first. I don't game in the extreme dark and I don't have a glossy screen -- but maybe I'm in the minority?