I don't feel inclined to tell someone my opinion at what they are wearing or trying to portray. I understand they have a reason they choose to hide their faces. I would be inclined to wear sunglasses as it kind of portrays a bit of mystery in my play, but I would not be the type to wear a scarf or outright cover my face. Unless they are doing something unusual and not allowed I would tend to just let them focus on how they look, might distract them from the actual game.