The Dutch CBP recently decided that monitoring people in and around commercial shops by tracking their mobile phone WiFi-signal without notice for analysis is against Dutch law. The ECJ judged in František Ryneš that monitoring the footpath in public space with a surveillance camera is in general a violation of EU law. Both authorities rejected collecting and processing personal data in ‘public space’ without consent or notification, as digitalization of public space has become a global trend nowadays, resulting in escalating privacy threat of multiple forms. Based on case analysis and conceptual construction, this chapter seeks to address the scope of reasonable ‘expectation of privacy’ in digitalized public spaces. It elaborates: (a) the genera of public spaces, including commercial venues, governmental utilities, even private properties, etc., and their related characteristics; (b) the functionalities of concealment and exposure of personal information in multiple public spaces, for instance, to achieve safety, identity establishment, autonomy, dignity, mutual trust, public participation, cooperation and economic efficiency; (c) the substantial impacts brought about by the increasing digitalization of public spaces, especially regarding the functionalities of personal information concealment; and therefore (d) the justified, reasonable ‘privacy expectation’ in public spaces, and feasible thresholds for safeguard.