@Walter Hinteler,
It's more a psychological effect - like searching shelter in a church or hospital, what many here did during WWII (and died there).
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During the cold war with Russia, here in the USA, each and every Tuesday at about 10:30 am, while I was in school in Chicago, we had air raid drills and the fire alarms rang for several minutes. The kids had to hide(!) under their desks and if you were in your car, you were supposed to stop, get out of your car and lay down next to the curb, until the sirens stopped.
I don't think it was psychological for most folks, since we all thought for sure the Russians were going to bomb us. Incidentally, we still have air raid shelters in many towns in New England. And some folks still have air raid shelters adjacent to their homes.