  In 1996, D.H. Rischke and M. Gyulassy proposed to use the time-delay signal
in Bose-Einstein correlations (BEC) as a signature for the possible formation
of a quark-gluon plasma (QGP) in relativistic heavy-ion collisions. In
particular, they suggested to measure the ratio of the transversal
interferometry radii, $R_{out}/R_{side}$, which can be obtained by fitting
experimental BEC data with a parametrization introduced by G. Bertsch et al. in
1988. The transverse radius parameter $R_{out}$ has compared to the transverse
radius parameter $R_{side}$ an additional temporal dependence which should be
sensitive to a prolonged lifetime of a fireball, in case a QGP was formed in a
relativistic heavy-ion collision. In my presentation, I am going to revisit the
above made considerations by addressing various possible scenarios for hadron
spectra (single and double inclusives) for Pb+Pb collisions at CERN/SPS beam
energies and for Au+Au collisions at BNL/RHIC beam energies, respectively,
within a relativistic {\it true} hydrodynamic framework (i.e., HYLANDER-C). I
claim, that the time-delay signal in Bose-Einstein correlations {\it is not} a
signature for the possible formation of a QGP, and I am going to explain why
this is the case.
