I suspect this is a deformation of the English "no-go", a term that comes up a lot in reference to Radio-Frequency IDentification systems, i.e. those "magnetic" tags on clothes in a shop.

One site on the Ouèbbe describing the duties of a sales assistant lists "Mise sur cintre, knogottage, mise en rayon". I can well see such devices being pinned on once a garment is on its hanger, and obviously before it is put on display in the store.