The Australian pics I saw appeared to show construction comparable to ours - either drywall over studs, or drywall on firring strips over masonry (block) walls. Some of the cavities were also stuffed with faced fiberglass.
I thank you all for granting me the courtesy of not dismissing my report out of hand. I'm reasonably sure my source was not pulling my leg - though Aussies have been known to tell some whoppers! The pictures are found on "the other" major electrical contractors' forum. If a mod asks, I'll post a link.
To my mind, wiring without boxes is simple heresy. I don't even like doing CATV that way, and mobile home methods horrify me. (Bet you'd never guess I learned the trade in Chicago
) Still, the Auie pics have me wondering ....
Drywall is combustible, eh? Toss a chunk into your BBQ this weekend, and report on what happens.