It's easy to fix the app so that it does not need the phone number and to have the app notify the user of the need to get a test instead of having a contact tracer having to double handle the information and ring the user. I believe the fact the app is doing this more about its heritage than any design here, however as an "Australian innovation" we could fix this and avoid the prospect of vulnerable people being rung up by people pretending to be contact tracers, which will happen, and will not be good when it does. Interestingly if the phone number is not stored, the need to store any potentially personal information will probably disappear as well.

There's no need to see the source code to recognise this is a problem. Could we at least lobby them to fix this? It would make life easier for the contract tracers and it would mean that people could rely on the app's secure channel, so if a scammer does call them they could confidently tell them where to get off.