>Suppose it turned out that for a private law based, anarchocapitalistic
>society to work effectivelly, it was necessary for people who shared the
>same legal system to live near each other.
I suspect that will be true to at least some extent, simply because people are likely to want to live near others with similar beliefs... and because PPAs are likely to charge a lot more for people who choose to live near to those who support very different legal systems, as that will greatly increase their enforcement costs.
>Aren't these two systems the same? What would be the difference between
>a world of competing miniarchies and an anarchocapitalist world where
>people's choice of law determines where they live?
They're very similar, but I don't see that the government system is at all realistic: I can't see any government choosing to let people secede, because no governor likes to lose their power. Plus in the anarcho-capitalist society I'd at least have the choice of staying where I was and paying the extra cost for a different PPA if I so chose.