For the purpose of illustration, let us first assume an anarcho-capitalist society. Though convinced that such a society is the only social order that can be defended as just, I do not want to explain here why this is the case. Instead, I will employ it as a conceptual benchmark, because this will help clear up the fundamental misconception of most contemporary free immigration advocates.
All land is privately owned, including all streets, rivers, airports, harbors, etc. With respect to some pieces of land, the property title may be unrestricted; that is, the owner is permitted to do with his property whatever he pleases as long as he does not physically damage the property owned by others. With respect to other territories, the property title may be more or less severely restricted. As is currently the case in some housing developments, the owner may be bound by contractual limitations on what he can do with his property (voluntary zoning), which might include residential vs. commercial use, no buildings more than four stories high, no sale or rent to Jews, Germans, Catholics, homosexuals, Haitians, families with or without children, or smokers, for example.
Clearly, under this scenario there exists
no such thing as freedom of immigration. Rather, there exists
the freedom of many independent private property owners to admit or exclude others from their own property in accordance with their own unrestricted or restricted property titles. Admission to some territories might be easy, while to others it might be nearly impossible. In any case, however, admission to the property of the admitting person does not imply a "freedom to move around," [u]unless other property owners consent to such movements. There will be as much immigration or non-immigration, inclusivity or exclusivity, desegregation or segregation, non-discrimination or discrimination based on racial, ethnic, linguistic, religious, cultural or whatever other grounds as individual owners or associations of individual owners allow.
Note that none of this, not even the most exclusive form of segregationism, has anything to do with a rejection of free trade and the adoption of protectionism. From the fact that one does not want to associate with or live in the neighborhood of Blacks, Turks, Catholics or Hindus, etc., it does not follow that one does not want to trade with them from a distance. To the contrary,
it is precisely the absolute voluntariness of human association and separation –
the absence of any form of forced integration –
that makes peaceful relationships – free trade – between culturally, racially, ethnically, or religiously distinct people possible.
http://www.lewrockwell.com/orig/hermann-hoppe1.html