Back in the '80's I used to do quite a bit of international driving, USA, Mexico, Guatemala & Honduras. Looking back it was really great, no computers, get stopped and usually a small "lunch donation" and you got to keep going on your way.
Now with computers, no more lunch money....
International driving today, best to be prepared with as much factual knowledge as possible cause now everyone has internet access and can verify or discredit anything you say in a heartbeat.
I found this website that provides really good information on International driving. There is a link for a PDF document of which I only briefly skimmed thru but on page 30 it does address International licensing.
Not really sure if it fits in with the Canada question but...maybe it does?
Enjoy the reading and let us know..