But... but! If you sell N cars exceeding the limit, someone else will sell the other N cars of the 2N in your "2N conforming cars" in the other possibility, and they'd emit, too! Or does selling N cars exceeding the limit somehow eliminates the demand for the other N?

I mean you can say that the limit is too low, but I don't understand this N/2N argument at all.

Also, I dunno about pitchforks, but if I park illegally, I'll get a ticket, even though maybe the parking restrictions are wrong in some important sense, and I'd sorta like it if law applied to corporations. If that's a pitchfork then it's a pitchfork to fine me for how I park my car.