I wondered about the same thing:

Re: Coruscant apartment codes. The architecture of the city is one of those giddy treats for city geeks. All those sleek Moderne towers and endless urban canyons. One of the best sequences consisted of Vader and Padme looking into the city, considering their fates; the camera moved slowly between the towers, for no particular reason; what, do the astral project when troubled? But any excuse for a flythrough. It’s just a cool place. But. BUT. For God’s sake, why aren’t there any railings anywhere? You build a docking pad so people can visit your 127th floor apartment, but you don’t build a railing? It’s windy up there. I’d get out of my car and crawl on my belly to the porch, and I wouldn’t stand up until I saw something I could grab. Like the hostess.

Read all of James Lileks' "disconnected observations" on "Revenge of the Sith" in today's Bleat.