Shonfield,
I too was required to have a non-pilot preference for my third preference.
Although on assessment day I asked both the defence interviewer and psychologist to be only tested for my two pilot preferences (RAAF ADFA and RAAF DEO) which they allowed.
So if its something you don't really want to do but rather just to have a non pilot job down because it was requested of you, mention it to your defence interviewer and psychologist as soon as you start so you can just be assessed for pilot.
Lacho
