Row 2: the event-horizon analogy

Consequently, a narrative in which qubits “leak across the cut” must specify an actual transfer interface or an access change. For example, an isometry

may return $S$ to the observer, changing the next accessible factor to $R\otimes S$. Alternatively, explicitly granting the observer access to the old $B$ changes the recovery problem without changing the global state.

For $V_{\mathrm{hidden}}$, the observer with $R$ alone cannot recover. An observer with $R\otimes B$ can recover by Theorem thm:global. These are different access contracts, not conflicting conclusions.

The split $R\mid B$ constructs neither a null surface nor a metric. It carries no area monotonicity, Lorentzian causal structure, or gravitational trapping statement. The no-signalling identity is not the classical area theorem BardeenCarterHawking1973.