In Nazi Germany, the Hitler Jugend, Deutsches Jungvolk and Bund Deutscher Mädel all wore a black neckerchief as part of their uniform, usually folded under the shirt collar.
In the late 50s and early 60s an élite group of leaders formed a troop called the 1st Larch Hill (note the similarity with the 1st Gilwell Park) which wore a grey neckerchief and acted as a proto-National Training Team.
The 5th Bolton Scout Group and the 5th Potters Bar Scout Group wear the scarf, (neckerchief/necker) officially, with permission from the Queen, and the Queen's Bands (of Queen's University) wear the tartan as part of their official uniforms.