I had the same question about legality in the US - even with CSWs listed on the AKC/FSS registry (AKC is the primary dog registry for US). I believe our humane societies (I read this somewhere or another in my research) will not adopt out any dog between F1 and F5 (not CSW, but dogs mixed with timberwolf,etc.), but after that it is ok. Most modern CSW puppies are F5 or after, from what I can see. But I'm not certain how that would work in a court. I agree that any imported dog should be a great "ambassador" for the breed in it's new country.
Marcy