  Gravitational wave templates used in current searches for binary black holes
omit the effects of precession of the orbital plane and higher order modes.
While this omission seems not to impact the detection of sources having mass
ratios and spins similar to those of GW150914, even for total masses $M >
200M_{\odot}$; we show that it can cause large fractional losses of sensitive
volume for binaries with mass ratio $q \geq 4$ and $M>100M_{\odot}$, measured
the detector frame. For the highest precessing cases, this is true even when
the source is face-on to the detector. Quantitatively, we show that the
aforementioned omission can lead to fractional losses of sensitive volume of
$\sim15\%$, reaching $>25\%$ for the worst cases studied. Loss estimates are
obtained by evaluating the effectualness of the SEOBNRv2-ROM double spin model,
currently used in binary black hole searches, towards gravitational wave
signals from precessing binaries computed by means of numerical relativity. We
conclude that, for sources with $q \geq 4$, a reliable search for binary black
holes heavier than $M>100M_\odot$ needs to consider the effects of higher order
modes and precession. The latter seems specially necessary when Advanced LIGO
reaches its design sensitivity.
