 FAKE: Refueling booms have that cone on the end for several reasons:  one is stability; another is to help guide the refueling probe into  the receptacle. By shooting off that cone the boom would whip around  so violently that it would be impossible to pinpoint its end. Also,  inside that cone are protrusions which interact on the aircraft  probe valve system to allow the passage of fuel. Without that  interaction, the interlock on the probe would never open.