LEAVE YOUR PREFERENCES. DO NOT CHANGE YOUR PREFERENCES BASED ON HOW LIKELY YOU THINK IT IS THAT YOU'LL GET INTO A COURSE.
Sorry to hijack the thread partly, but I'm curious to know if this (the part I bolded) is actually true. Disclaimer: I totally agree that the OP should leave it as their first preference even if they don't think they have the ATAR.
Anyway, I have a hunch that many interview and scholarship offers are made after considering a student's placement of a course on the preference list. In fact, I believe this information is relayed to universities from VTAC.
Anecdotally (which doesn't actually stand for much), I've seen scholarship offers made to myself and others generally come from universities which aren't first on one's list in an attempt to entice people to go to a uni. This makes sense, given that a uni has no real reason to throw money at you to come if they already know they're first on your list. However, as more concrete evidence, on my enrolment information on my.unimelb, I can inspect my course info and it details that Biomedicine was my 2nd preference (I just left chancellors as #1), which is true and clearly indicative of the fact that the uni knew this info.
Can anyone say for sure?