We're talking about many centuries before your irrelevant census point. A 2 or 20 person society is relevant on a theoretical level.
Go look on wikipedia for the earliest abolition of slavery:
https://en.wikipedia.org/wiki/Abolition_of_slavery_timeline
>1117: Slavery abolished in Iceland.
After the early rush of settlers, the need for external slaves became unnecessary because the population eclipsed exploitable resources.
Whatever bullshit objection like small population or they are "backwards" subsistence farmers is irrelevant to the fact that civil order was maintained by polycentric law for 3 centuries. Could it work today? Your type won't even allow the experiment so people are forced into schemes like seasteading or "free cities" in Central America.