As for "should have anticipated the potential consequences", how could they not have anticipated them? America was founded with the understanding that states had a hefty degree of autonomy, so centuries later, it's well understood, is it not? Any state law might not be valid across the border, this has been true since America came into existence, so why should these be any different?
As for the airport legal computer screen, I don't know if any of it is right or wrong, legally speaking, I was just trying to paint a picture of the absurdity of trying to protect locals from all possible different legal situations in all possible destinations.