The seawall looks like a path. It is also the edge of the city, and edges have to be checked. Every walker, runner and cyclist on the seawall, and every person who cannot sleep and goes for a walk along the water at two in the morning, is checking it without knowing.
In Terminal City their movement is what keeps the edge in place. A person tracing the city's edge, again and again, holds that edge where it is. When the movement thins out, a stretch of path or shoreline can start to drift, or a lamp repeats itself farther around the bend than it should.
The Green Static scrambles the Circuit's signals around Stanley Park, and somewhere near Wreck Beach there is a gap it has never fully closed. The rule is the shortest one in the city.