It seems that it is a common enough occurence that Airbnb needs to address it. I felt horrible writing the title for this reply, we conditioned not to single out races or nationalities, and that is of course completely appropriate. But when the incidence of this kind of unacceptable behavior is so much higher among specific groups of people, then I think it Airbnb should respond. I know that when I get an inquiry from someone from China or Korea I am immediately on guard. I don't assume anything. I make clear in all my communications with them prior to their arrival what the expectations are, and I will no longer accept guests from China or Korea without glowing reviews.