5Miles..
Very True. However Melbourne Facilities (or at least the Liaison Officer) will only allow you to visit once you have been given a Panel Interview Date. (This could've changed over the past 9mths though)
Brisbane however didn't stipulate the same rules. It may also be different now though?
I was lucky enough to have a lot of exposure to ATC whilst in the RAAF.
But yes, I agree with you.. one should get insight to the job even prior to applying.