Independent checks that are not independent

What it looks like. A second opinion is required and obtained. The reviewers share training, priors, source material, or model lineage. Escalation exists and routes to a tier that reasons the same way as the tier below it.

Why it fails. Correlated reviewers produce agreement, and agreement is read as confirmation. The control reports consensus while providing no additional information.

Instead. Require periodic independent re-interpretation of consequential artifacts by reviewers with no access to prior labels, and treat low variance as a monoculture signal rather than a quality signal. Maintain an explicit escalation graph with tier responsibilities and alert on tier-skip patterns. Separate instances of the same model are not independent reviewers.