That's not necessarily AusPost's fault.
As soon as the sender puts the shipping info into AusPost's systems, for example by printing an AusPost shipping label, it'll show up with that. That doesn't mean the sender has actually posted the item, or that AusPost has actually picked it up from them.
You usually get another event in the tracking system when it's actually been picked up or scanned through a distribution centre.
Yeah. I recently had something sent where the label got printed several days before it package actually got picked up and send.
Oddly enough the tracking email that austpost sent once it shipped estimated longer than it actually took. So I guess huzzah AustPost.