Decoherence

Decoherence is the fading of the relative phase between the amplitudes as a qubit couples to its surroundings, often alongside a drift toward its lowest energy level. The chances of 0 and 1 can outlast that fading, so a machine may still print bits after it has lost the cancellations those bits were meant to show.

Keith says the quantumness has leaked out of the box, which at least points at a box. Malcolm says the detail has moved into the surroundings, where the experiment is not writing it down, and his version tells you where a later measurement would have to look.