Reply #29: But part of the experiment is also whether they ever leave.

[Inland]

Suppose that the experiment is declared a "failure" in that the owner gets poorer, or finds his toothpaste being pilfered or nobody washing the dishes. He says, "okay, everyone out". The experiment is still continuing to see if the "guests" leave voluntarily. Maybe they didn't understand that the experiment was to see if the owner enjoyed the experience. Maybe they think it's unfair for them to pack up and move in just to be forced out later. And maybe your nosy neighbor will come over and tell you how much better the entire neighborhood is from the experience...without offering help, natch.