I would also like to see this functionality added to Survey123. I need a way to prevent the folks using my surveys from pre-populating answers. I need them to answer each question every time....and not "cheat!"
Maybe a new column in the XLS form can be added that can be set by the survey maker to prevent any given question from being saved as a favorite. In my case, I'd set all of my questions in the XLS to use this function, preventing my users from being able to save their favorites.