They've Breached Our Walls!

I don't know about you guys, but I would love to see public events in the City, where a group of enemies are attacking one of the perimeter City Districts. Then the Guardians will go to defend the City, and for the rest of the day that part of the City would be damaged from the fighting, and would be fixed by the next day. Of course, these events should be rare, and should be a tough challenge. Having public events like this would emphasize the City's vulnerability, and the enemy's efforts to destroy us. Yes, I know that the Traveler has magic protecting the City, but what if that magic only prevents aerial attacks. If there's a breach in the wall, the enemy could surely launch a small invasion from there. What do you guys think?