I don't get the complaints about not having real plates/cups. When I'm sick, I don't care what I have.
They do the same thing if they isolate someone to the cabin for stomach concerns. A few weeks ago my sister went to medical with sun poisoning or a stomach bug, and they isolated her. Everything from room service was in disposal fashion.
They also delivered room service on disembarkation day. I had no idea she had ordered anything and was the only one who heard the knocks so I was confused when I answered.