A home's sellers are morally obliged to include with the sale of the home at least some of the appliances that are not permanent fixtures but were in the home when it was shown to prospective buyers. A home's sellers are morally obliged to ensure that prospective buyers of the home do not assume that any large appliances are permanent fixtures in the home. If a home's sellers have indicated in some way that a large appliance is included with the home's purchase, then they are morally obliged not to remove that appliance after showing the home. If a home's sellers will be keeping any belongings that prospective buyers of the home might assume would be included with the purchase of the home, the sellers are morally obliged to indicate clearly that those belongings are not included.
Real estate agent: Upon selling a home, the sellers are legally entitled to remove any items that are not permanent fixtures. Legally, large appliances like dishwashers are not permanent fixtures. However, since many prospective buyers of the home are likely to assume that large appliances in the home would be included with its purchase, sellers who will be keeping the appliances are morally obliged either to remove them before showing the home or to indicate in some other way that the appliances are not included.
Which one of the following principles, if valid, most helps to justify the real estate agent's argumentation?