Could be that they gave her the umbrella to handle herself, taking an additional risk of a serious fall, in order to project a more healthy image of her. By contrast, carrying her umbrella may have projected the notion of weakness or of royal entitlement.
With the left, issues of political correctness outweigh health considerations.
One of the first things I noticed was how she was gripping/reaching for the stair-rails like it was all she could do to get up the steps..