No no no ... I'm not talking about Shel Silverstein Books ... I'm talking about Zone Map Edges.
Every MMORPG has to find a method to "contain" Players within the Zone Maps. Most Zone Maps are effectively "buckets" that the Players have to stay inside of.
City of Heroes did this most famously with the War Walls to enforce the "bucket" of the Zone the Players were meant to stay within.
Praetoria dispensed with the War Walls, instead resorting to Sonic Fence Pylons in order to enforce "containment" of Players (by "killing" you and forcing you to Rez back inside the Zone Map boundaries if you strayed too far "out of bounds").
World of Warcraft resorts to the "falling off the edge/mountain" principle in a lot of cases, where if you stray too far "out of bounds" beyond the edge of the map your character just starts dying (with the added penalty of potentially being in a place that is impossible to retrieve your corpse from).
Tabula Rasa employed both methods ... where some maps were a walled "bucket" you couldn't climb out of, while other maps had "edges" that fell into chasms where if you "fell off the edge" then it was a hospital trip for you to Rez and resume play.
TERA does both methods as well, although in practice it's more a matter of "invisible walls" preventing you from falling over the edges of the maps (like a stupid dumb block of wood). Heck, the tutorial area in TERA, even before you reach your first Foe NPC has a Guard telling you not to get yourself killed crossing a guarded and well patrolled bridge if you click on them. The bridge, of course, spans a chasm that would be "instant death" if you fell down into it ... which, of course, you can't because there's invisible walls all around preventing you from making a Swan Dive Into Suicide before you even get attacked by a Foe NPC.
The point that I want to make here is that there are essentially two "methods" of containment typically employed to keep Players within the boundaries of Zone Maps ... either "walls" of the "can't go there" variety, or by "killing" the Player (fairly or unfairly) so as to force them to "return" to the interior of the Zone Map. I propose a third alternative for dealing with "Edge Cases" for Zone Maps. I recommend, for City of Titans, a simple ... Log Out.
To use the situation of Praetoria/First Ward/Night Ward, which lacked "barrier" type walls, in a City of Titans context ... what would happen is that if a Player went "off the edge" in a direction that does not lead into a defined space (ie. another Zone Map) then the Player will be given a 10 second warning (much like the Sonic Fence Pylons did) and if the Player has not exited from the "danger zone" at the edge of the map within those 10 seconds, they'll simply be Logged Out of the game. Log back in and you'll be relocated onto the "safe" side of the edge of the Zone Map where you'd gone "out of bounds" for too long.
Note: in a Day Jobs styled context, logging out "beyond the edge" could effectively become a Day Job in and of itself, in either a "commuter" or other long distance "traveler" sort of sense. The key being that there actually *IS* a World beyond the edges of the game's defined maps, even if you can't get to it (YET!).
Doing things this way, where going "over the edge" of the map doesn't "kill" your character or have the boundaries enforced by visible/invisible walls makes the game inherently more extensible in a way that allows the Environment Devs to "build their way out" from whatever the center of town is to encompass the desired areas to expand the game outwards to. It could even allow for the relatively "rapid" development of new neighborhoods and locations that lie "just beyond the edge" of the currently playable area ... AND it allows Zone Maps to be any shape at all desired by the Environment Team since the "edge" of the map is defined as being wherever they want it to be, rather than something enforced by a set of right angles that encloses a defined space. And because "going off the edge" of the Zone Maps merely causes a Log Out instead of a "death" (complete with penalty?) there aren't any potential continuity problems with having the "map edges" retreat over time and the Environment Team completes work on more areas of the City of Titans ... whereas doing things like "busting down the War Walls" in City of Heroes would have caused all kinds of continuity issues/questions to arise (and did in the case of Vanguard's base in the Rikti War Zone).
Verbogeny is one of many pleasurettes afforded a creatific thinkerizer.