The selection of Hymn Warriors is recommended by their own civilizations and nations, and then uniformly assessed for recruitment. Maintaining a certain number of star warriors is vitally important to all major civilizations, as it directly determines the execution right to a "dispute" and the authority of their own discourse.
Though rules exist, when it comes to implementation, there will inevitably be subjective differences. This is an unwritten rule, also a reserved space. There is no absolute fairness; the powerful always strive for greater rights, while the weak need to strive.
Within the Star Alliance, those who choose to lay low usually don't fare so well.