Item 123: The sharp bankroll across a reopening, and the cushion exploit against the pinned market maker

Across one reopening the proved bankroll is −3ρ(2 + ρ) (WarrantEntitlement.netWorth_ge_neg_odds_reopened, Fixture.liability_rebutted); the dispatch's 3ρ is refuted by an exact two-phase exhibit (projects/normativity/rounds/2026-10-21-rebuttal-and-end-to-end/src/exhibit.py::cushion_exhibit, 24 > 12 on the fixture) in which a counterparty's gains on the rebutted row cushion its later selling, and the per-row accounting gives odds_A(3 + 3·odds_S) = 27. Three gaps: the exhibit runs a one-coordinate maker, not the pinned MarketMaker (as item 114); the sharp constant between 24 and 72 is not determined; and whether a settlement-time accounting of the reopened mass (charging the counterparty's gain on a rebutted row at the rebuttal, as the rule charges the enforcer) restores 3ρ is a design question for the maintainer, queued.

Deliverable shape: the exploit against history L E with the trader exhibited, or the obstruction; the sharp constant for one reopening; the accounting variant if adopted. Acceptance check: Lean green; the exhibit's numbers recomputed by the fixture. Context: projects/normativity/rounds/2026-10-21-rebuttal-and-end-to-end/REBUTTAL.md A2; items 114, 40.