I have just visited (and tagged) 6 points on the Black Allan line (The straight bit of the NSW Victoria border in Australia). By joining the dots up we now have a better approximation of a segment of a great circle that this border is supposed to be.
It also means that a bridge near Delegate (on Bonang Road) returns to its rightful place in NSW.
I hope that some intrepid OSM'ers will treck to the two endpoints of this line, since the current OSM co-ordinates seem to be about 200 metres SSW of the co-ordinates given by GeoScience Australia and Google Maps/Earth.
PS I then mapped the Bonang Road down to Orbost and I think that this may the twistyest road (of serious length) in Australia, maybe the world. You drive for weel over an hour and you are almost always turning the steering wheel.