I have zero doubt that Clinton's campaign employs graphic artists, photographers and editors to frame PR images to her visual advantage, including some cloning and manipulation but there is zero chance they would produce something this amateurish.
If it was me, I would have an archive of hundreds of crowd files from every angle and lightening scenario so I could build crowd layers that match the scene and do not repeat anyone (never mind repeating some obvious ginger dork 12 times) - and I would VERY sparingly use that to fill in a spot here and there.