Anyways, the structure of the Psi-Cops is hardly something original from
Babylon5.  Even other stories that included mages had them in highly
secretive, secluded towers, where initiates are pulled from the general
population as very young children.

The inspriation comes from real life orders that do the same thing.  The
Shao-Lin Monks, for instance, may not practice magic, but they do accept
initiates who are young boys barely 5 or 6 years old, who then spend the
rest of their lives training in the monastry.