A reaction I sometimes get to this work is that: "Maldacena showed in AdS that measuring a certain correlator can determine whether black hole evolution is unitary (i.e., whether information is destroyed)". That is correct, but the measurement precision needs to be of order exp(-S), where S is the entropy of the hole. It turns out that is the same level of precision one needs to detect decohered Everett branches of a system with S degrees of freedom.
The black hole information paradox and macroscopic superpositions
We investigate the experimental capabilities required to test whether black holes destroy information. We show that an experiment capable of illuminating the information puzzle must necessarily be able to detect or manipulate macroscopic superpositions (i.e., Everett branches). Hence, it could also address the fundamental question of decoherence versus wavefunction collapse.
Comments: 10 pages, 4 figures, contribution to proceedings of the 1st Mediterranean Conference on Classical and Quantum Gravity.