thans biff44,
i see your point, but in a flyback, the output diode will be turned on, and the core will thus be de-magnetized.
the output diode will take some time to turn ON, -but so would the diode in the RCD snubber.
I am afraid i am still unsure as to the real purpose of the RCD snubber that appears across the FET.
Also, to an extent the transformer capacitances and fet drain-source capacitance will absorb some of the flyback energy, up until the point when the secondary diode turns ON.