Handshaking is performed, by an ego device via a wireless transceiver, with surrounding mobile devices to receive identifiers of the surrounding mobile devices and incoming notification messages from the surrounding mobile devices. Each of the incoming notification messages are sent from a different respective sender device of the surrounding mobile devices and include identifiers of devices seen by the sender device and an indication of whether issues with the devices seen by the sender device were identified by the sender device. An alert is raised responsive to an issue being indicated with the ego device based on the incoming notification messages.