Originally Posted by dddc
...over the issue of whether a US born citizen must travel on a US passport to the US. Don't know if Australia is like this, but I wouldn't dream of entering Australia on anything but my Australian passort!!
To get back into Australia on a non-Australian passport, you need to have a re-entry visa. It's quite possible that a cross-check would occur at that point to determine if you have an Australian passport.
I know a case about 10 years ago of an American woman who came to live in Australia, married to her Australian husband, and became a citizen of Australia. I don't know whose requirement it was, but she had to renounce her American citizenship at the time, which she did.
A couple of years later she applied for a visa to go back to the States with her new family, and was rejected. Turns out visas can't be given to American citizens. Applied for a U.S. passport and was given one.
Perhaps this explains the "softening" of the Australian requirement to renounce all others. It doesn't really work.