A method for generating an alert on a mobile device in an absence of a radio-frequency identification (RFID) tag in proximity to the mobile device is provided herein. The method comprises defining an event. A profile list for storing RFID tag identifiers is related to the event. The method also comprises sharing the event data together with the profile list using a social media network, storing all received RFID tag identifiers at a time within the duration of the event after an event start time in the profile list if the profile list was empty before the event start time, and generating the alert under alert conditions. The alert conditions comprise a determination that the profile list was not empty before the event start time, and that one RFID tag identifier stored in the profile list is not among the received RFID tag identifiers during the event duration after the event time.