The matter here is interstate students don't do their UNSW interviews until *after* this Jan offer round, so UAC doesn't know whether they will or they won't get a UNSW offer. But read on ...
In the past UAC used to have a pref status code saying like "Qualified for, offer not (yet) made pending result of a higher pref". If you see this code on your UAC application for WSU then you know that's the case. However this code seems to have disappeared from UAC list, thus I wrote above UAC may now give you the WSU offer regardless of UNSW outcome later.
(This would be at the expense of someone waiting in line for WSU, since if you also get a UNSW offer in Feb you can sit on both until March while the other student has nothing). Edited to add from
LMG! <--- don't do this, anyone reading along!! (as in, don't sit on both offers until March), be kind to your fellow med-wannabes and decline any unwanted offers ASAP. Please and thank you.