Many moons ago when I worked in Sydney ATC, the game was the same. As long as the aircraft had asked for pushback and taxy they were allowed to depart.
It was rare, but the pilots and ATC had an understanding, and pretended not to 'notice' the bags still being loaded, the aerobridge still connected,no pushback tug,etc.
Mind you in those days the Transport Minister ( Big Tony)and Plibarsek weren't the local members for the area.