We’d like to refer people to looking over the policy on NPC usage, as per the helpfile on NPCs.

A particular addendum should be made, namely that non-Open NPCs are particularly not to be used as emitted characters without expressed permission. Even in those cases where permission is granted, our preferred policy is that they are “seen and not heard”, rather than becoming major parts of a scene. In the future, we will attempt to make those cases where permission is granted clearer, either by setting up a puppeted object controlled by an approved player, or by creating a +job set at Player level which anyone could refer to.

When in doubt as to whether an NPC is being used with permission, please feel free to discuss it both with those using the character and with the staff.