Tribes, clans and circles section about entering a tribe from slavery edited to say
Some slaves will have an idea of their bloodline when they are freed, because at least in some places the Amarr maintain those lines (eg slaves are sold as “pure Sebiestor”, or “mix of Krusual and Brutor”, or “mongrel”). We have to assume at least some, possibly most, would not have this information, though, or be of a very mixed line. A process where refugees learn about the ways of the tribes, with the help of a refugee center or on their own, and then choose which one to apply to is often assumed by players of former slaves; some assume a process where a tribe is simply assigned to you. Genetic testing could help in choosing but would in practice be unlikely to reveal conclusive information on everyone (due to mixed lines and how genetic markers actually work). Who exactly decides who gets to enter which tribe and on what basis, is quite unspecified. Given the size and resources of the Republic, the number of refugees, and differences in tribal and regional customs, it is possibly unlikely the process would be similar for every port of entry and every refugee center, so interpretations can easily co-exist.