If we're talking about the nuts and bolts of the game (UI, textures, models, animations, levels, lighting, physics, AI), than one could say, rightly, that the whole game is 'scripted', although perhaps 'coded' would be a better term. But a game has to have every last portion of it 'coded'. An AI can't do anything if it has no protocols to follow, and thus requires numerous scripts to tell it what to do in certain situations. By scripted, I think you guys mean scripted as in like a movie, where the same characters do the same thing every time, which isn't the case.
The AI is certainly following scripts, but they don't say 'Do this every time when the player appears.' They say instead 'If the player does this, do this, but if he does this, do something else entirely.' This adds an element of 'randomness' and change to each play-through. Perhaps there are scripts that randomly choose different AI spawns and weapon load outs. Again, scripted, but not in the way you think.
