In any intelligence agency it is important to keep track of crank contacts, not only to improve protection but also to assure continuity of control and analysis. Centralization of records in CIA’s Office of Security permits quick identification of phonies and time-wasters. Professional security officers know how to handle the off-beat approach, and others would do well to rely on the professionals when they receive an irrational letter or find themselves face to face with an apparently unbalanced stranger.
https://www.cia.gov/library/center-for-the-study-of-intelligence/kent-csi/vol9no3/html/v09i3a09p_0001.htm