[huac]

Even though we may not build overt, physical defense mechanisms into our cities, our cities are still in many ways engineered for defense. Drones, SWAT, surveillance, checkpoints, security zones - all of these techniques are employed, from Baghdad to New York, to exert control. So while we don't build walls to keep people out anymore, we certainly still build defenses to protect us from the people already inside the city. What I disagree with the author on is scale - all of these countermeasures are still on a larger scale - it makes more sense for a city government to enact safeguards, than it does for individual buildings. There really hasn't been a disappearance of large, city-wide protection systems, you just can't see them as obviously.