In a similar vein, nobody would notice the old woman sitting at the railway station, knitting away, waiting for a train. In fact, what she was doing was including coded details into her knitting of train & troop movements, to be passed onto the Resistance at the end of the day.
Lots of brave people contributed to the war effort in surreptitious ways.
She was not old at that time, but a teenager, and her cover to observe german positions was, according to article being an itinerant seller of SOAP in a bicycle.
Being a young woman, according to the wikipedia, she was also able to entertain conversations with the young german soldiers to gather more information.
It looks like the knitting kit was just a clever way of having a place to hide the OTP codes she used and keeping track of the ones already used. Also, according to the wikipedia she was once detained by the germans for interrogation, but they didn't think of checking her hair tie.
Pretty clever IMHO, not to mention the mind-boggling level of courage.
It also mentions the subject of OP's article too. I have seen an old piece of knitting from WW2 used to convey messages in a military museum in Portsmouth, UK.
Lots of brave people contributed to the war effort in surreptitious ways.