Your comment about nationality seems interesting - it's a fundamental human right to have nationality (https://www.ohchr.org/EN/Issues/Pages/Nationality.aspx);

Your comment about nationality seems interesting - it's a fundamental human right to have nationality (https://www.ohchr.org/EN/Issues/Pages/Nationality.aspx); https://www.ohchr.org/EN/Issues/Pages/Nationality.aspx); what do you mean by "non national persons" ? The common mass cases e.g. illegal immigrants are not non-national persons, they're just nationals of some other country. There are certain edge cases that result in stateless people, but the general solution for that is for states to work to assign nationality, it's definitely reasonable in many countries to not be able to have standard contracts with such people until they get their identity documents issued.