They encourage people around City Hall to follow the "No Idle Zone" they've proclaimed. They also have signage at certain drive throughs, for obvious reasons. However, trying to push a no idling when it's a place that gets to -40 C, well, that's a bit difficult. If such a law were passed and a commissionaire is willing to stand outside in -40 at a hair above minimum wage to write me an idling ticket, I say have at it.
When it's -40 C, the parking enforcement goes down the toilet. If they passed a non-idling bylaw, I suspect we'd see the same.