—With the wide spread deployment of wireless LANs (WLANs), it is becoming necessary to conduct analysis of libraries of measurements taken from such operational networks. The availability of these trace libraries can be quite useful to provide realistic models of network load and user mobility, among others. To maintain user privacy, techniques of trace anonymization may be used to hide information. In this paper, we propose to study the fundamental trade off between the utility of WLAN traces and its privacy. The study provides several realistic case studies in which privacy attacks may be conducted, and questions the efficacy of existing anonymization techniques. Our initial quantitative analysis to estimate mobile users’ k-anonymity in WLAN traces shows surprisingly unique usage patterns, which may compromise anonymity. The main contribution of this paper is to articulate the compelling challenges facing anonymization of wireless networks traces and to shed some light on the an...