  Boson-sampling is a highly simplified, but non-universal, approach to
implementing optical quantum computation. It was shown by Aaronson and Arkhipov
that this protocol cannot be efficiently classically simulated unless the
polynomial hierarchy collapses, which would be a shocking result in
computational complexity theory. Based on this, numerous authors have made the
claim that experimental boson-sampling would provide evidence against, or
disprove, the Extended Church-Turing thesis -- that any physically realisable
system can be efficiently simulated on a Turing machine. We argue against this
claim on the basis that, under a general, physically realistic independent
error model, boson-sampling does not implement a provably hard computational
problem in the asymptotic limit of large systems.
