I think you are incorrect about that.....someone asked that question a week or so ago and it was answered. There is a law that states, (correct me if I am wrong) no matter where the product is made if it is sold in the "good ole USofA" and if it infringes on a USA patent then it is ripe for infringement action. Also I believe there are international treaties that deal with patent infringement between countries.
It only makes sense. A company located here could grab up the best and latest "tech" device created in Korea, or wherever, manufacture and sell it only in the USA and not be liable for infringement.....I don't think that would fly