OK...Then you would say that if China stationed troops# and WMD aimed at Aus population centres that that would have nothing to do with Aus and that we under such circumstances cop it sweet because its solely PNG's sovereign right to do what it wants...eh?
# China's Shanghai Cooperation Organisation (a Mini-NATO)
So as the saying goes: "Be careful what you wish for (eg Ukraine's right to join NATO and harbour NATO troops and WMDs aimed at Russia) because China might take that as a nod and a wink (say no more) to do ditto to Aus using the SCO in PNG, East Timor or the Solomons etc etc.
IMO if PNG ever had concrete plans to allow Chinese personnel & WMD on their territory we'd knock them over and see to it that a new Pr0-Aus regime was installed pronto.
DSo the bottom line in Geo-Politics is : Be careful what you wish for...eh?