At a camp fire, sitting round the fire, there is a lot of warm glow from the fire - but away from the fire, the evening cool is at your back. To be comfortable sitting round the fire, it became customary for campers to wrap themselves in blankets.
Over time it became customary to decorate the blankets, which were commonly ex-army wool blankets - and in some cases to turn them into poncho-type garments. This decoration could take the form of applique or embroidery, and many fascinating designs could be seen.
From the 1970s onwards, the decorated blankets tended to be replaced by blanket patches, and as a result more campsites started to stock and sell badges. Wool blankets became less common, replaced initially by the wool 'travel rug', and more recently by fleece blankets.