Violation of the FRW consistency condition as a signature of
  backreaction
  We propose a backreaction toy model with realistic features and confront it
with the Union2.1 supernova data. The model provides a good fit even though the
expansion history is quite different from the LCDM model and the effective
equation of state is far from -1. We discuss compatibility (or lack thereof)
with other observations. We show that the FRW consistency condition between
distance and expansion rate is violated with an amplitude that is slightly
below the current observational limits. We expect that this is also the case in
the real universe if backreaction is significant, providing a distinct
signature of backreaction.
