Cooperative wireless networks, enabled by Cognitive Radios, facilitate mobile users to dynamically share access to spectrum. However, spectrum bands can be accessed illegitimately by malicious users. Therefore, the success of dynamic spectrum sharing relies on automated enforcement of spectrum policies. While the focus has been on ex ante spectrum enforcement, this work explores new approaches to address efficient ex post spectrum enforcement. The main objective of this work is to ensure maximum coverage of the area of enforcement and accurate detection of spectrum access violation. The first objective is achieved with the help of Lloyd's algorithm to divide the enforcement area into a set of uniformly sized coverage regions. The interference detection accuracy is achieved through crowdsourcing of the spectrum access monitoring to volunteers, based on their computational capabilities, location attributes and reputation. A simulation framework was developed in CSIM19 (C++ version) to analyze the performance of the proposed system over the entire area of enforcement. The results show that the proposed scheme ensures efficient coverage of all the channels and regions in the area of enforcement and a high average accuracy of detection.