In various geopolitical contexts, a strategy of flexibility exists in the urban politics involved in governing extralegal or informal practices, yet the actual processes involved have not really been analysed. This paper is based on a case study of the informal management of street vendors in Taipei's Shilin Night Market. The city deploys a policy of loose policing of the extralegal vendors, demonstrating its will to improve the situation, and the vendors respond by performing a series of spatial routines in order to maintain their occupancy of appropriated arcades and streets. This ritualised interaction, explored here in the light of Ervin Goffman's performance theory, allows the municipality to accommodate informality within a contemporary urban context. The paper analyses the political, social and spatial significance of this informal management in order to clarify one of the ways in which modern cities can benefit from urban policies and planning strategies that support urban informality.