Found that New York has a snitch program for enforcing their Idling laws:
$87.50 for 3 Minutes: Inside the Hot Market for Videos of Idling Trucks
I'm not going to get into whether the law itself is good or bad, because how much pollution idling trucks produce isn't something I know a lot about.
I'd assume that they idle for some the the same reasons I've left my car running in a parking lot though. Weather conditions can suck, and sometimes you don't want to run down your battery while using it for a long period of time.
But incentivizing citizens to tattle on other citizens for cash feels really scummy to me.
new york city has a history of scummy behavor