A method, comprising: receiving, by a user device and from a first beacon device , a proximity message; activating, by the user device , a scan mode based on the proximity message; receiving, by a zone device , a first message broadcast by a second beacon device , the first message including a first identifier; the first identifier being associated with the second beacon device ; receiving, by the user device and from the second beacon device , the first message based on the scan mode; determining, by the user device , the first identifier based on the first message; activating, by the user device , a broadcast mode to broadcast a second response message, wherein the user device broadcasts the second response message for a threshold amount of time and/or a threshold quantity of response messages; and providing, by the user device and to the zone device , the second message including a second identifier, the user device hence providing the second message to the zone device without establishing a communication link with the zone device , wherein the second identifier is associated with the user device and the first identifier, determining by the zone device an identifier of the user device based on the second identifier and the first identifier, determining, by the zone device , an event associated with the identifier of the user device based on the first identifier; and providing, by the zone device , to a server device , information that identifies the identifier of the user device and the event to permit the server device to identify a displacement trajectory associated with the user device . receiving, by a user device and from a first beacon device , a proximity message; activating, by the user device , a scan mode based on the proximity message; receiving, by a zone device , a first message broadcast by a second beacon device , the first message including a first identifier; the first identifier being associated with the second beacon device ; receiving, by the user device and from the second beacon device , the first message based on the scan mode; determining, by the user device , the first identifier based on the first message; activating, by the user device , a broadcast mode to broadcast a second response message, wherein the user device broadcasts the second response message for a threshold amount of time and/or a threshold quantity of response messages; and providing, by the user device and to the zone device , the second message including a second identifier, the user device hence providing the second message to the zone device without establishing a communication link with the zone device , wherein the second identifier is associated with the user device and the first identifier, determining by the zone device an identifier of the user device based on the second identifier and the first identifier, determining, by the zone device , an event associated with the identifier of the user device based on the first identifier; and providing, by the zone device , to a server device , information that identifies the identifier of the user device and the event to permit the server device to identify a displacement trajectory associated with the user device . <EOS>