  The nonlocal conductance and the current cross-correlations are investigated
within scattering theory for three-terminal normal metal-superconductor-normal
metal (NSN) hybrid structures. The positive cross-correlations at high
transparency found by M\'elin, Benjamin and Martin [Phys. Rev. B 77, 094512
(2008)] are not due to crossed Andreev reflection. On the other hand, local
processes can be enhanced by reflectionless tunneling but this mechanism has
little influence on nonlocal processes and on current cross-correlations.
Therefore Cooper pair splitting cannot be enhanced by reflectionless tunneling.
Overall, this shows that NSN structures with highly transparent or effectively
highly transparent interfaces are not suited to experimentally producing
entangled split pairs of electrons.
