Once again, there are numerous points of failure along the way that led to this incident, but if you take the (hypothetical) point of view of a lawyer representing the plaintiffs in any case such as this, the aircraft Captain always retains the ultimate responsibility for ensuring he is aware of the pertinent details regarding the conduct of an IFR flight before undertaking such a flight. Yes, that places a major dependency on Flt Ops, but it doesn't remove the responsibility from the Captain. I have yet to see an ANO or FAR directive that relates to the execution of IFR flights by LCC's or Airlines with short turn around times, excluding them from receiving a comprehensive and current IFR pre-flight briefing.