You'll want to check out this previous post on these boards:
http://www.kia-forums.com/t9436-service-campaign-notice.htm
According to the service dept at my dealership, Canada is affected by this but has yet to get the parts out to the dealerships, that's why we've yet to get a service campaign notice. The parts are supposed to be arriving soon, I've been told (they thought last week, but seems they didn't arrive).
How I found out: My car is overheating just from sitting, waiting for the light to turn green. I checked for the sticker/yellow dot it says in the notice mentioned in the above post and found I didn't have either. The Rad Cap Assembly does need to be replaced, badly, but there's nothing they can do until they get the part. This has been confirmed with my dealership. Seems because the flow/pressure is all wrong, the engines will, over time, start to get too hot, even if the coolant has been topped up.
Makes getting stuck in traffic really tricky.
Anyway, check the above post, check your car, and if you think you are affected, call your dealership, let them know, and see when they are getting the parts in so you can get it fixed asap.
And while I'm posting... anyone know what sort of damage will be done to an engine if it gets too hot a lot?