That's been standard policy for some twenty four centuries now, as laid down in Pericles' Funeral Oration by Thucydides: "Our city is thrown open to the world,

That's been standard policy for some twenty four centuries now, as laid down in Pericles' Funeral Oration by Thucydides: "Our city is thrown open to the world, though and we never expel a foreigner and prevent him from seeing or learning anything of which the secret if revealed to an enemy might profit him." http://hrlibrary.umn.edu/education/thucydides.html http://hrlibrary.umn.edu/education/thucydides.html (It mostly works, especially allowing for some, or a lot of, bending of truth in advertising.)