The municipalities are desperate for cash. They're doing tons of "Click It or Ticket" stings, and that means they can also check registrations and inspections, brake lights, and so on. They're getting tons of money from this stuff.
Haha, for a second there I had visions of these people going round breaking brake lights just so they can fine you for broken brake lights.
The economic situation in some of these towns is so desperate, nothing would surprise me!