If the buyer is an American buyer, then U.S. law applies. The Canadian supplier would get whatever protection that law provides. We hope, then, that if this act were passed, the USDA would declare that the U.S. system would protect that Canadian seller.
Now, if it's the other way around and it's a U.S. seller and a Canadian buyer, this act would protect the U.S. seller. It's complete reciprocity.