Why is Sia covering her face? Does she think someone will recognize her?
The multiple camera flashes from the paparazzi can be blinding. She is merely covering her eyes. Reason Rob is looking downward. Have you ever had your pic taken by one camera and one flash and been blinded afterwards with that white spot in your vision? Well, that's why.
Sia should be covering her boobs! You can see them through that sheer blouse (with no bra)! Wonder if Rob likes that?