Comment by wongarsu

All of those are methods to be resistant to aerial bombardment in my book.

If nobody knows where your factory is, it looks like a parking lot from the air and you have multiple smaller factories instead of one big factory to mitigate the impact of a damage event you are resistant to aerial bombardment, even if your ceiling isn't any sturdier than a normal factory roof. Same if the factory is out in the open but everybody thinks your drone factory produces windshield wipers