1. A first mobile device, comprising: a processor; a communications interface; and a search module; wherein: the search module is configured to initiate an autonomously electronic search for a target tag associated with a moveable object at least in part by transmitting a first search activation signal; the first search activation signal is configured to: cause a second mobile device to search for the target tag; and when the target tag is not detected by the second mobile device, to cause the second mobile device to transmit a second search activation signal, the second search activation signal configured to cause a third mobile device to search for said target tag.