Aus and us share forces almost routinely. Not a lot of americans go there full time in our off season, I think it has something to do with aus firemen being unpaid volunteers in many cases, whereas our guys get paid full time. I don't remember all the particulars, I was not a fulltime fireman, as outside the fire season I had a real job as a forester. I had a foot in both camps which enabled me to rise in both fields. (Until the "spotted owl" injunctions, during which time the research branch hired me during the winter, until it got resolved via the Northwest Forest Plan)