In the Legion of Lawndale Heroes universe, the New York City Exclusion Zone is an area surrounding the City of New York (out to about twenty miles) where the provisions of the Bowman Acts are not generally enforced by the United States Government except when absolutely necessary. The full reasoning for this has never been fully disclosed; however, one reason for this is that it would interfere with the longstanding rules of diplomatic immunity and the sovereign nature of diplomatic areas being considered foreign soil. Moreover, even though a number of the nations within are signatories to the Bowman Acts, the United Nations, as a legislative body, does not recognize them.
The effect of the Zone has been the development of an underground metahuman culture that has always existed within the city itself, but expanded greatly upon the passage of the Acts and the announcement (through secret channels) of the Zone's creation. This has also led to the viewing of New York City as an 'open city', and a 'safe haven' for people with those abilities, which has led many metahumans (and their families) to begin new lives and careers in the area.
Harlem, in particular, has become an area where metahumans congregate for business and pleasureful pursuits; as such, the area has profited immensely. Coney Island, for many years in decline, has also experienced an economic resurgence so profound (beginning in the late 1990's) that many businesses in the area, including the various amusement parks, have been able to plan major upgrades and expansions on their various holdings because of the influx of metahuman visitors from around the world and alien visitors from off-world.
Of course, the clear and overt use of metahuman abilities in public within the Zone (for anything except cases of extreme emergency when lives are in imminent danger) is still considered to be a violation of the Bowman Acts. Very few metahumans (even criminal elements) violate this sanction, as all understand that the Zone's existence is a good thing for all concerned - and that when violators are seen as worthy of the government's attention for violations, the penalties are usually extraordinarily severe.
It is noted in the Bowman Acts that the New York City Exclusion Zone is one of six such areas in the United States officially set up and recognized for this purpose; the cities of Los Angeles, Austin, Orlando, Seattle and Chicago have also been designated as Exclusion Zones, with the same rules and provisions in place. None (with the exception of Los Angeles and Austin)., have anywhere near the assimilation and overt nature of the metahuman culture of New York City.
The organization known as Special Unit 2 has a dedicated presence in all cities with Exclusion Zones, and metahumans who live in such areas are informed of their existence as a specialized arm of local law-enforcement that deals in the specific needs of the community.