That is because of the "tag" function of a POB for the Whitelist ( docking allowed ) and the Blacklist no docking allowed.
He can simply add for example : Shadow , as tag and all ships that are named Shadow will be hostile. That is to make it easier if you want to denie acces for a faction for example.
Edit: You should name each ship diffrent, not like Shadow 1, Shadow 2 Shadow 3.. and so on. Because IT COULD, only could and only if you are nitpicky be seens as " Faction tag" what would mean this would apply :
3.9 Having more than 1 ID per Tag. Faction Tags Rules can be found Here.