Truueee but I've also never heard of a pet shop/breeder in Nevada selling ferrets to California citizens and getting in trouble because of it.
I guess I sort of view the repercussions of such a deal as all on the buyer because they know that what they are doing is illegal and the seller isn't responsible to learn the life story of the buyer.
It's kind of like when you walk into a tobacco shop and see all the pipes and bongs. The seller doesn't ask what they are going to be putting in the bong, they just sell them the bong. It's the responsibility of the buyer if they decide to break the law or not. I know inanimate objects are a poor comparison but I hope I illustrate my view well enough.
Now, the seller WOULD be liable if s/he shipped the animal to another state themselves, but not if someone else drove it across state lines.