Complete instruments rather than scalar records

Preservation of an unconditional reference marginal alone is weaker than identity transmission. Likewise equal classical records need not mean equal residual instruments CheungI,CheungVIIJ, CheungEn09A. For example, the identity channel and computational-basis dephasing may return the same deterministic record while their residual outputs on $|+⟩$ have trace distance $1/2$.