There’s a recent paper by Debasis Bhattacharya Mario Canul and Saxon Knight of the University of Hawaii on the Impact of the Physical Web and BLE Beacons (pdf). The paper is based on a project that uses Eddystone Ephemeral-ID (EID). The paper is more a backgrounder and description rather than providing new insights. Nevertheless, it provides a useful description of some security issues with beacons that include tracking of beacon locations, forgery and showrooming.