[hollerith]

It would easy to tell: (unless they were occupied by only a handful of people) they would be useless as fallout shelters without a lot of ventilation, and you can't rely on the wind: you'd need big fans and ducts, and the fans would need to keep running after most of the electricity-generating capacity available in Tokyo is destroyed, i.e., this ventilation system would need its own hardened electricity supply.

[bobthepanda]

Also, using this as a shelter would have a pretty obvious downside if torrential rainstorms happened.

[tharkun__]

Never mind all the wasted space above peoples' heads. The picture further down has people walking. They're tiny.