  We show that the formalism commonly used to implement Bose-Einstein
correlations in Monte-Carlo simulations can lead to values of the two-particle
correlator significantly smaller than unity, in the case of sources with strong
position-momentum correlations. This is more pronounced when the phase space of
the emitted particles is strongly reduced by experimental acceptance or
kinematic analysis selections. It is inconsistent with general principles
according to which the Bose-Einstein correlator is larger than unity. This
inconsistency seems to be rooted in the fact that quantum mechanical
localization properties are not taken into account properly.
