A story that circulated in the latter days of World War Two ... about 1944-45.
First it is necessary to understand that anyone with a German or German-sounding last name was often the focus of suspicion.
The story goes :
One day a nosy neighbor picked up a piece of paper dropped by a neighbor of German descent. Seeing it was a series of numbers and letters he turned it in to the FBI. After several days of unsuccessfully trying to break the code and watching the woman the FBI brought her in for questioning.
She was told " We know you are a spy. We have a code you dropped and that was turned in to us. We want you to translate this for us."
They handed her a note that read k1P2,k3,change,knit three , (etc)
She promptly responded laughing : "Oh, that's where it went. It's the instructions for a cable stitch sweater I am knitting for my daughter."