Mmm, know what you mean - I had the same thing happen with Lost - I thought Claire's accent was fake at first (noooo, the actress is Aussie, and I've never heard her natural accent before). As you say, bunch of Aussies, doesn't bother me (I love Farscape and it doesn't bug me then).

It's probably that everyone is so used to Americans and Brits cropping up in movies that we don't really give it any thought. But evidently we're so unused to hearing an Aussie accent in that mix, and that's why it sounds weird to us. If that made any sense? (You know, if I knew what the hell I was really talking about, I'd write meta about this, but I really don't).