I was about to say the same thing.
All Australian packages have ID recorded stickers on them, that get put on by Australia Post when the packages get sent.
All packages sent out of Australia have those stickers on them.
That is so if an Australian sends drugs to another country, and that country's customs catches them, then it can be tracked back to the sender as the Australian sender had to show photo ID when they sent the package.
Anyway, regarding Radar's package, that wouldn't have been opened by US customs at all, or anyone else for that matter and certainly his address wouldn't be flagged from it. ID Recorded stickers are standard procedure for packages out of Australia.