At my theater, we a had a faulty fire alarm that seemed to go off every few weeks, but we still had to evacuate everybody anyway just in case. When it went off, all projectors shut down, fire lights blinked, and we had an automated system telling people to please evacuate the building.
It never failed that people would come up to the service desk asking for a refund on tickets and concession.
Our standard response was "Once the fire department clears the building for re-entry, then we will issue a refund."
Unfortunately, this was often not good enough for many people, but we could normally not get them to leave until they saw us employees exit the building. Then they would follow to bug us outside.
Almost as much fun as the people who showed up, oblivious to the fire trucks and hundreds of people outside, that tried to enter the building.