[_carbyau_]

Honestly, seems like a couldn't-hurt move.

Too close? Incinerated. Doesn't matter.

Goldilocks nearby enough for glass shrapnel? Dodged some glass by being under desk! Win!

Far away? Heard a distant boom while under desk.

Hard to fault really.

[unsupp0rted]

The tradeoff is raising generations of children terrified of nukes destroying their world at any moment. Better safe than sorry, as you suggested, but it's not a zero cost strategy.

[_carbyau_]

While true, at that point in time the parents were also similarly terrified.

Schools educate children to fit into society.

That was society at the time.