I think a series of false alarms would have the effect you describe. However, based on some of the reactions I'm seeing online, I wonder if a one-off false ala

I think a series of false alarms would have the effect you describe. However, based on some of the reactions I'm seeing online, I wonder if a one-off false alarm will cause a lot of people to figure out what they should be doing if the alarm were to go off again for real.