Question for Aussies: WTF?

[maxd]

Okay, so I was watching a recent BBC documentary -- Simon Reeve in Australia or whatever it's called -- and in part two he visits an armoured mobile division of the Oz army stationed near Darwin. These guys are loaded for bear: APCs, M1A1 Abrams tanks and so forth. Doc showed them watching the coastline, tramping around in the bush eating bugs and playing survivalists etc but never actually said WHY they were there. Apparently the USofA is going to station 2500 troops there as well.

Question is .. why are they there? Was there something specific that happened that prompted this or is it just a preparedness thing, which is what the show more or less implied. Seemed like a lot of dancing and not much music but maybe I missed something. Do tell.