Fly_emirates,not so in SAS.The ramp agent knocks on the door to signal that jetbridge is in proper position,and auto levelling is operating.Then the cabin crew opens door and confirms that all is O.K. for pax disembarkation.Then the "self loading cargo" leaves the plane.
In the Concorde with no windows in the door,there's no way the cabin crew would be able to signal that door is O.K. to open from the outside,accordingly,the cabin crew does this job themselves.
"Luck and superstition wins all the time"!