In the real world, the phone number for CNA is a closely guarded secret. Although the phone companies finally caught on and these days are less generous about handing out information so readily, at the time they operated on a variation of speakeasy security that security professionals call security through obscurity. They presumed that anybody who called CNA and knew the proper lingo ("Customer service. CNA on 555-1234, please," for example) was a person authorized to have the information.