"But the idea that someone might be arming the Seam would never have been allowed" — why "would have"?

Question

From The Hunger Games:

My bow is a rarity, crafted by my father along with a few others that I keep well hidden in the woods, carefully wrapped in waterproof covers. My father could have made good money selling them, but if the officials found out he would have been publicly executed for inciting a rebellion. Most of the Peacekeepers turn a blind eye to the few of us who hunt because they’re as hungry for fresh meat as anybody is. In fact, they’re among our best customers. But the idea that someone might be arming the Seam would never have been allowed.

I'm not sure I understand why the sentence uses would never have been instead of would never be. The protagonist's father died a long time ago; that's why she's talking about him in the past tense. The book itself is written in the present tense. The Seam is the district where the protagonist lives.

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Here's my guess:

If I rewrote the sentence in the present tense, I think I'd get:

But the idea that someone might/may be arming the Seam has never been allowed.

To make it hypothetical, I would need to replace has with would have; I also wouldn't be able to use may:

But the idea that someone might be arming the Seam would never have been allowed.

I suppose would never be would work if the present tense version used is never:

But the idea that someone might/may be arming the Seam is never allowed.

But the idea that someone might be arming the Seam would never be allowed.

The difference is that this version refers only to the present while the original sentence refers to the past up to the present.

Answer 1

It's a kind of variation on the third-conditional / hypothetical. It describes a past situation that didn't happen, and the potential consequence if it had happened. Here's how it could be phrased as a standard example of the third conditional:

If her father had sold the bows, it would have given the government the idea that her father was arming the Seam, which the government would not have allowed.

To get the sentence in the book,

1. remove the redundant "if" clause and imply it with the simple conjugation "but".
2. simply imply the relationship between "selling bows" and "the idea someone is arming the Seam".
3. change to the passive form

But (if her father had sold bows, then) the idea of someone arming the Seam (by selling them bows) would not have been allowed.

You may notice Katniss leaves vague what exactly would not have "been allowed" and how the Peacekeepers would have stopped it. The reader is meant to fill in this gap with their own imagination.

It's also an example of the relaxed style of Katniss' narration and the overall way in which Collins writes. The book is at a "young adult" reading level, so even though the themes are fairly mature the writing itself is relatively simple. It doesn't explain every detail, or get sidetracked with long digressions that might bore younger readers. It says just enough for the reader to get the idea, then moves on.