The IOA security guys I encountered when I was staying late taking pictures last month were pretty unpleasant. I was up at the LC/Suess transition trying to get a good picture when all of a sudden I hear "Ok, that's enough, this is your last picture and get moving!" I heard them grumbling as I caught up to the pack of tourists that were lingering closer to the Port of Entry which allowed me a few more pictures. It seems they're in a hurry to get everyone out. Very different experience to Disney, where they'll usually politely chat and even be sure to stay out of your way when you're staying late for pictures.