I haven’t seen this anywhere and I’m surprised. If you go through the Wassailer clothing set and equip each item there’s a big conflict. The Brocade Waistcoat has a neckerchief built into it so equipping the Wassailer Neckerchief along with it is just messy looking. They also clip into each other. And then there’s the color choice. If you have the Black, Blue, or Green waistcoat, the built in neckerchief is red. If you have the Red waistcoat, the neckerchief is black. The Festive Wassailer set has the same issue as the faction colored sets.
tl;dr: The separate Neckerchief clothing item doesn’t seem to belong in the Wassailer set.