From the 501st Legion Charter:
The Legion Membership Officer (LMO) is responsible for receiving and processing applications for membership. In doing so, it becomes his/her responsibility to issue and track all identification numbers (i.e. 'TK' numbers), guaranteeing their uniqueness. The LMO uses the accompanying application photos to make a determination as to the initial qualifying costume as well as all subsequent requests for additional costume recognition and approval. This approval is based upon the official costume list and official visual reference guide. The LMO is the immediate supervisor to all Garrison Membership Liaisons (GMLs), and serves as the manager of the Legion GML forums. The LMO will conduct (via the GMLs) an annual census of the membership for the purpose of verifying contact information and costume status, and to make the appropriate status assessment and classification. The LMO will respond to initial membership inquiries and handle all issues where membership and/or costume status are concerned. He/she also reviews all applications for new Detachments, ensuring that the requirements are met, and that the costumes covered are well defined and do not infringe on existing costume Detachments.