Why do cops drive their vehicles with light bulbs out?

I saw a local cop car driving at night with a headlight out, 2 months later I see it driving around at night again with a headlight out. Possibly a different car in the same department with another headlight out, but I doubt it. How do you write someone a ticket when your vehicle isn't legal itself?
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+1 y
A headlight being out is pretty obvious when they get out of the car multiple times every night to pull someone over.
Why do cops drive their vehicles with light bulbs out?
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