A ski-lift hold model dropped a chair line and nobody can reconstruct the reason from the weights. An explainability add-on might sketch a local reason, but it is not widely available and the vendor warns it can slow the hold decision. What safety problem should the tester explain?

Weights that cannot narrate why a chair line dropped are a safety problem: limited explainability and transparency. Current explanation aids are partial and may slow the hold decision. They are not complete and free, and a Chapter 5 label-correctness procedure is not the explanation.