A non-Japanese friend of mine got a very bad reputation from the landlord. Generally he was not interested in keeping his house clean, nor was his Japanese wife. They allowed the child to come in barefoot without washing. The tatami mats seemed sandy, and the couple apparently did not clean the bathtub enough. It was so dirty that the landlord had to substitute a new one after they moved. They sometimes held drinking parties at midnight, and the neighbors complained of this.
Through a real estate agent, I advised the landlord that, through his own experiences, he could tell a non-Japanese specifically what to do or not to do with regard to Japanese social customs in the framework of a contract arrangement. I'm sure that non-Japanese with common sense can understand the customs, and sometimes they have a keener sense about a contract than Japanese people. Basically Japan is a country of nonverbal communication, but Japan must now become a country of verbal communication to the rest of the world.