Answer:
The Husband, Wife, and Neighbours due to Xenophobia kept increasing the security apparatus of their living space.
It is interesting to note that the fear was not based on fact or any logical deduction. For instance, one family had a maid that was an outsider working on the inside of their home. Not once did they think that she could harm them. Yet, they would install various kinds of technology to protect themselves from potentially harmful outsiders that never even showed up for once.
The theme of the story is captured in one word - Xenophobia. Xenophobia is simply a fear of outsiders. An expounded version would be the Dangers of Xenophobia.
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