Step Turn, I enjoy your posts. It seems that Canada, Australia and NZ all approach the business of SAR in a similar way.
If I do want or need to file a flight plan in Australia or NZ (which I might do simply for the purpose of having a SARtime in the system) then all I have to do is go online. In fact that's the way that ATS in both countries prefer it to be done.
I certainly don't have to tell the airport operator what I'm doing. Indeed there are hundreds of Class G airports where there's nobody to talk to anyway.