One of the most frequent passengers is the VicPol photographer. They will sit there for quite a while depending on the situation taking snaps from all angles or as scrambler says, searching for clues / bodies etc. Would be surprised if the coroner was on board. They normally arrive in the unmarked wagon complete with aluminium suitcases and tinted windows.
I can't see that the news choppers have any more rights to be there than the TigerMoth and vice-versa. In all honesty and crudeness, what's happening on the ground is irrelevant.
Move on and get over it!
That being said, it's quite a tragedy and unfortunate that they didn't get out of the car as it appeared to be only in about 6ft of water.