What are the conditions underlying successful implementation of participatory security mechanisms? Drawing on the case of Ciudad Nezahualcóyotl and from the notion of social embeddedness, we argue that participatory security reforms that aim to include citizens in defining security priorities allow for better adoption of reforms in practice. Local level reforms are not implemented in a social vacuum but rather in pre-existing social networks that are key to their adoption in practice by citizens. However, not all social networks are equal, nor do they operate in the same manner. In ‘Neza’, it is through existing clientelistic networks and socially embedded local brokers that the redes vecinales were implemented and adopted by citizens, leading to varied reform adoption patterns at the very local level.