Apparently, some car enthusiasts have decided that breaking the flow and uniform color of a car's body with holes for things like lights is unseemly. Especially in the forums of Corvette and Mustang fans, you can find instructions and kits for smoothing over distracters like reverse lights, driving lights and even head- and taillights. Many of these blackouts are illegal on street-driven cars and are intended only for display or showroom use.
But again, should we really need laws that stop us from blacking out headlights? For those still scratching their heads: Lights were put on cars for a reason, namely so that you can see where you're going, other drivers can see you and you can signal your intentions to change your path to other drivers. Going into stealth mode on the road may seem like fun, but so does becoming a ninja hit man, and if you've ever seen old kung fu movies, you know that ninja hit men never live very long.