The chances are that the person GWB was being photographed with had been 'vetted' prior to the visit, being asked about his views and stuff like that, the President doesn't just turn up and chance meeting someone who might give him a load of verbal, so there could well be some kind of freebie going on with him or something similar of that nature. Anyone who has ever been in the military will know that's what happens whenever a big name gets shown around to 'kiss babies'.
It happens lots of other places too, for example, when I worked at a paper a few years back, Tony Blair came to the premises as part of the drive for the Commonwealth Games in Manchester, the paper I worked at being one of the big sponsors. He was kept well clear of the 'peasants' (i.e. all us workers), as he probably would have received a few choice comments, and at the time the editor was sucking up to him big time, writing lots of creeping fawning letters on the editorial page (probably after a knighthood or something). Actually, I did bump into TB on that visit, he was coming through the canteen when I went down there for a cigarette and a cup of tea, and he came breezing through (with his jacket off and sleeves rolled up, that being TB's attempt to look like one of the people), and the editor was tailing along behind him like some kind of faithful puppy, it was embarrassing to watch actually, all the editor needed to do to make himself have any less dignity would have been to wring a cap in his hands.
Trust me, those kind of visits are more rehearsed and stage-managed than a West End show.
Chock