Kidou Senshi Gundam 00I
Summary
Mobile Suit Gundam 00I ("I" for Innovades) is the manga sequel and replacement for Mobile Suit Gundam 00F. It was also written by Tomohiro Chiba and illustrated by Kōichi Tokita. The story runs concurrent with Season 2 of Mobile Suit Gundam 00 and tells the story of a young man, named Leif Recitativo, who was ordered by Veda to gather a group of living bio-terminals called Innovades. Members of Celestial Being's shadow group Fereshte (which is now disbanded and rejoined the main organization) reappear as a supporting cast to the main characters. (Source: Gundam Wiki)
In a system like that there would need to be rigorous documentation and certificates of prior ownership/guardianship or else anyone and everyone would just get grabbed off the street and enslaved at any time, and such a society would collapse instantly. So these slavers wouldn't have such documentation unless it was a forgery since the kids were just kidnapped; both offenses should be very serious capitol crimes. Once again, the day is saved by glorious Bureaucracy! (and the MC's knowledge and exploitation there of).