I was watching people, always an instructive activity. It was a hot, humid afternoon in Manhattan with an on-again-off-again threat of showers. Around Union Square, nothing more reached the ground than an few light sprinkles. It was sensible for people to carry an umbrella and more than a few did. After a sprinkle, you could still see one or two people walking about under their umbrellas, even in a crowd of people going about bare headed. The sprinkles having come and gone rather gradually, these few never notice it had ceased to rain and went about with one hand tied up protecting them from rain that was not there. If "parasol" was even a word in the working vocabularies of these people, I would be a bit surprised. There wasn't much sun anyway. If you let the scene go out of focus, it would remind you of Seurat's "Sunday Afternoon on the Island of La Grande Jatte" but if you look closely you might see instead a form of neurosis.
From the personal to the national, if your protective measures make you unaware of your actual state of threat, you are, at the very best, wasting your resources.