If the buyer is picking up the tab to ship to Canuckistan. There's no loss to the seller except the time.
What's the big deal?
Oh, too many other important things to do?
In my experience, people never believe true shipping costs for international shipping. Also, since we generally get paid via paypal, the buyer is always right in a dispute and Paypal refunds the cash. I've been told by Paypal directly not to ship via USPS internationally because their tracking info is not sufficient.
Perhaps someone has had an international dispute and can correct me if USPS's info was sufficient?