  We perform a critical re-analysis and discussion of recent results presented
in the literature which interpret the CMa overdensity as the signature of an
accreting dwarf galaxy or a new substructure within the Galaxy. Several issues
are addressed. We show that arguments against the ``warp'' interpretation are
based on an erroneous perception of the Milky Way. There is nothing anomalous
with colour--magnitude diagrams on opposite sides of the average warp mid-plane
being different. We witnessed the rise and fall of the blue plume population,
first attributed to young stars in a disrupting dwarf galaxy and now discarded
as a normal disc population. Similarly, there is nothing anomalous in the outer
thin+thick disc metallicities being low (-1<[Fe/H]<-0.5), and spiral arms (as
part of the thin disc) should, and do, warp. Most importantly, we show
unambiguously that, contrary to previous claims, the warp produces a stellar
overdensity that is distance-compatible with that observed in CMa.The CMa
over-density remains fully accounted for in a first order approach by Galactic
models without new substructures. Given the intrinsic uncertainties (concerning
the properties of the warp, flare and disc cutoff, the role of extinction and
degeneracy), minor deviations with respect to these models are not enough to
support the hypothesis of an accreted dwarf galaxy or new substructure within
the Milky Way disc.
