The City of Milwaukee has a new brilliant solution to the problem of loud cars:

Milwaukee aldermen voted overwhelmingly today to crack down on loud music from cars, by making it easier to file complaints against vehicle owners.

The Common Council voted 12-1 to approve a six-month pilot program that will allow citizens to report an alleged noise violation by giving police the vehicle's license plate number, the date and time of the noise, and the complainant's name and contact information.

Authorities then would send the vehicle owner a warning letter and charge the owner for the costs of enforcement on subsequent complaints, which could be as much as $100 for each violation. That procedure is similar to the city's nuisance property ordinance, which allows tickets and fines for property owners when police are repeatedly called to the same building.

Notice what's missing there?  Actual proof that you broke the law.  All that needs to happen is a neighbor sends a letter to the police.  The police never have to witness the violation, nor do there have to be separate individuals complaining.  So if you don't like your neighbor, why not just send a letter to the police and accuse them of a noise violation.  Do it a couple times, and they get charged a grand.  Brilliant plan.