Since most of our participants are in the US, it hasn't come up as far as I can remember.
In the case of gift certificates, I don't think it matters where you are. If the shipping cost is higher then you won't get as much with your order since more of the cost goes to pay for shipping.
If you're a winner you get to choose which prize you get, too, so you'd ideally choose the one that best matches the circumstances.
