I do not agree with Mrs. Shrek or with KiwiJay because Melbourne is the most logical stop on the entire globe, having been long overlooked by prior Amazing Races.
It could just be professional jealousy that Phil didn't bring them over the ditch to Kiwi-land,
but when I heard that they were supposedly spotted doing a task in Melbourne, I thought
this should be easish to confirm - busy location, English speaking country, lots of TAR fans, maybe a few tourists wandering around with cameras..... I have been doing loads of searches for any traces of another mention of sightings in Melbourne (granted I'm not an expert searcher so I could have missed something) and have found nothing. No more detail has come from the original spoiler either, and the poster did add a disclaimer that his mate could have been pulling his leg, which is why I am a doubter at the moment....
I do agree that if they did a really quick splash and dash in Melbourne, and then headed off somewhere like Tasmania, there would be more chance of keeping things quiet, so I'm not ruling Australia out totally yet.....let the search continue!