I'm glad I read your post because I just did a quick search on Civil War Spies. See some notable woman names on it, but the excerpt on George Curtis was interesting:
George Curtis was living in New York at the beginning of the war, and he joined a New York Infantry Regiment. He then became a Pinkerton agent, and a very good spy. He made his way to the Confederate capital as a contraband merchant selling gun caps, ammunition, and the much needed quinine. The day after reaching Virginia he was taken to the Confederate lines and to an audience with General Ambrose Powell Hill. General Hill gave him a pass to go on to Richmond and
also asked Curtis if he would carry some dispatches as well.
Hmmm-interesting, it seems even if you have a New York accent that as long as you have some quinine with you, the Confederates will give you secret dispatches...;-)
Not big on security I guess.