If they allowed gameplay on the show floor, I'd tear apart their oh-so-glorious FPS demos by standing around in 1 place while repeated scripted explosions rack the skyboxes around me & looping NPC chatter gets old, and tippy-toe back & forth to expose the lines triggering scripted events like a floor collapsing just in front of me, and then I'd run for minutes into every invisilbe wall of this open world corridor while my NPCs yell to move forward, and I'd fire on the friendlies which the game either won't allow or fail me for doing so. \n
In the Division, I'd play a total jerk, keep trying to break the game & mess with everyone friend or foe, and talk in incomprehensible slang & annoying voice/accent, as I'd expect to find in the real world outside this staged demo, and then proceed to do the same "open world" tests as with the FPS above. For the more 'cinematic' games, I'd fail every quicktime event and see if it makes any difference at all.