I has got easier in recent times, but I still struggle (as an Australian) to fill the form correctly. A human will check your domain order!
.au domains are restricted to Australians, Australian businesses, or those who have legit connections here.
For .com.au you will need Australian contact details, and an Australian business number (ABN, ACN etc).
If you use an Australian business as your proxy, then technically they will own the domain.
If you use fake information, you risk losing the domain.
I wouldn't be surprised if registrars look at your IP address....
THE GOOD NEWS is we get to trust .au websites, they are virtually spam and crap free.
THE BAD NEWS is that is hard for foreigners to enter this domain market.
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.us domains are similar. I use a US mail forwarding service and a US Skype phone number, and check the wrong boxes.... but none of my .us domains are precious.