Dualshock 4's light bar does not come with an off-switch
The DualShock 4 is a peculiar controller. And, according to Shuhei Yoshida, the controller's light bar does not come with an off switch. The upcoming controller is noted for its touch pad, new joy sticks, a more ergonomic shape, and its light bar. The light bar interacts in a fashion akin to the PlayStation Move. In motion-based games, the controller interacts with the PlayStation camera for better detection. Or, as demonstrated in Killzone: Shadow Fall, the light bar can be used as a health bar.
Shuhei Yoshida confirmed as much with a simple "no," in response to a question on Twitter he fielded.