@stratman, I see that today you're playing devil's advocate ..
As you know well, cartridges regionally coded have a different part number depending on the region. For instance PGI-2200XL Maxify carts for North America or PGI-2500XL for Western Europe.
Likewise for the PG-221/241 and PG-521/541 series.
Instead, all PFI carts, that I know of, have the same part number. You order a PFI-1000 cart for a Pro-1000, regardless of the country where you live.
I've got some OEM PFI carts at home. I use them to refill with Lucia ink my Pro-10s carts. Most of them are for older printers : PFI-105, PFI-107, PFI-303 etc but I have also a PFI-1100 CO for the Pro-2000/4000.
In none of these carts you'll find any written warning about the cart being restricted to an specific region.
In top that, at the back of the sticker, you can read the addresses of most Canon regional headquarters around the world: Europe, USA, Australia, Japan, implicitly meaning that the cart can be used anywhere.