Never heard of it either nor seen it to my knowledge. We have always just cut the tail hair "off" so it's short and straight. Easy to identify and don't get docked at market or hurt the hide value.
It is fairly common here. Mainly used when preg checking bigger herds. Breds get a straight line. Opens get a big O. Last much better than a paint stick. Really helpful when there will be more than one day running cows through.