One thing I'd add, fail closed gating just moves the quiet failure elsewhere unless you're monitoring quarantine and coverage rates as their own metrics, with thresholds from your own baselines and business impact, not mirrored off block rates. What bugs me is smth like a carrier gateway remap quarantining every brazilian record, and downstream just reads that as the market being absent. The strict defaults make sense since the code is scoped to one pipeline, mobile safari on product pages, but you'd generalize those as the fleet widens, same with the replay spec, a changing site never reproduces exactly anyway, what it buys you is auditability. Proxy's just one part of the instrument, and it only belongs behind validation that can actually reject bad price evidence