  In this paper we discuss quantum computational restrictions on the types of
thought experiments recently used by Almheiri, Marolf, Polchinski, and Sully to
argue against the smoothness of black hole horizons. We argue that the quantum
computations required to do these experiments take a time which is exponential
in the entropy of the black hole under study, and we show that for a wide
variety of black holes this prevents the experiments from being done. We
interpret our results as motivating a broader type of non-locality than is
usually considered in the context of black hole thought experiments, and claim
that once this type of non-locality is allowed there may be no need for
firewalls. Our results do not threaten the unitarity of of black hole
evaporation or the ability of advanced civilizations to test it.
