@Gargron Historically in the US false alarms have been due to selecting the wrong pre-configured message to issue during a scheduled test.
It happened at a national level back in 1971 -- http://conelrad.blogspot.com/2010/09/code-word-hatefulness-great-ebs-scare.html
@rfrederick @Gargron working in IT I'm actually surprised we haven't seen more of this, honestly. Other emergency warning systems have actually been 'hacked' due to poor authentication systems before.
Still mad though.
Not saying this was a hack though, could easily be an accident or misconfiguration.
@Gargron On the other hand, we have learned some important lessons from this. People didn't know where to go, and the roads instantly gridlocked. There was panic.
Hopefully the emergency management folks will take a good look at reports of this fiasco and design better protocols. Fill in the gaps, rework the parts that need it.