  In today's terrorism-prone and security-focused world, evacuation
emergencies, drills, and false alarms are becoming more and more common.
Compliance to an evacuation order made by an authority in case of emergency can
play a key role in the outcome of an emergency. In case an evacuee experiences
repeated emergency scenarios which may be a false alarm (e.g., an evacuation
drill, a false bomb threat, etc.) or an actual threat, the Aesop's cry wolf
effect (repeated false alarms decrease order compliance) can severely affect
his/her likelihood to evacuate. To analyse this key unsolved issue of
evacuation research, a game-theoretic approach is proposed. Game theory is used
to explore mutual best responses of an evacuee and an authority. In the
proposed model the authority obtains a signal of whether there is a threat or
not and decides whether to order an evacuation or not. The evacuee, after
receiving an evacuation order, subsequently decides whether to stay or leave
based on posterior beliefs that have been updated in response to the
authority's action. Best-responses are derived and Sequential equilibrium and
Perfect Bayesian Equilibrium are used as solution concepts (refining equilibria
with the intuitive criterion). Model results highlight the benefits of
announced evacuation drills and suggest that improving the accuracy of threat
detection can prevent large inefficiencies associated with the cry wolf effect.

Physics and Society