A short post on the NYTimes.com Caucus Blog gives a glimpse into what it's like to take part in a 'pool spray' - a presidential photo op that is very much like a run and gun event.
From the size of the crowd and the amount of shutters you hear firing I would guess the approach is a 'spray and pray' one - hoping that if you bracket and fire off as many exposures as you can that you'll get at least one good image.
I can't imagine what it must be like to be one of these photographyers. It would seem that all the joy and passion of taking images is completely gone when it comes to something like this.
Anyway, here's the link that contains a video of the event - just don't blink or you might miss it:
from NYTimes.com from The Online Photographer