Proposition: Pre-read coupling is a declared interaction

A unitary $U_{CX}$ before consumption replaces the instrument by ${\mathcal{M}}_C\circ {\mathrm{Ad}}_{U_{CX}}$. This may change the record law and residual states, but supplies no metric back-reaction.

Proof. Compose the Kraus operators with $U_{CX}$. Completeness is preserved because $U_{CX}$ is unitary. No component of the specified geometry has a state-dependent update equation.