(From the NSA Handbook)
As you depart NSA facilities, you will note another physical security safeguard--the inspection of the materials you are carrying. This inspection of your materials, conducted by Security Protective Officers, is designed to preclude the inadvertent removal of classified material. It is limited to any articles that you are carrying out of the facility and may include letters, briefcases, newspapers, notebooks, magazines, gym bags, and other such items. Although this practice may involve some inconvenience, it is conducted in your best interest, as well as being a sound security practice. The inconvenience can be considerably reduced if you keep to a minimum the number of personal articles that you remove from the Agency.