This is more than a little worrying as I thought that even with fuel mismanagement (this early in flight could not have been empty tank could it?) then the engines would still be gravity fed from wing tanks aided by engine driven low pressure pumps even with tank booster pumps off or failed. I know there is a note in QRH saying that degraded performance at high altitude is possible with both pumps in one tank failed (OFF) but it is not required to open crossfeed until such degradation occurs. Somehow I have never thought of FL240 as high altitude. I know its not low but not that high either. Obviously rethink required.