Lexington, KY has had an anti-idling ordinance/bylaw, whatever it's called; though I don't know the specifics of it. The only thing I know is that you cannot leave you car idling, though I think it specifies unattended, even if it's to warm up your car.
I've not heard much of people being ticketed for it. Police do use common sense and compassion when dealing with people; they're not nazis separated from us, but other people doing their jobs. I don't think that the police, at least not around here, are going to bother going around finding people's cars idling; they're rather going to use it, like many ordinances, where they have a complaint or where it is just plainly inviting somebody to steal it.
Such ordinances, though, are often passed by presumptuous, pompous, and out-of-touch city council members who just can't understand why somebody would need to leave their car running to warm it up in the luxury of their own garage.
