Package Damage by Customs?

This is highly unlikely as they have trained dogs to sniff for such things. They would also be very careful opening anything as to not destroy any evidence.

I can't answer for Australia, but in the US the packaging is actually carefully opened to preserve it as evidence if it turns out there is contraband in it. The packaging will probably have fingerprints of the person or persons who packaged the content and the delivery information all gets to be used against you in a court of law.

In most cases, the package and content will be X-rayed before anything destructive is done. If the content is damaged and no contrabands were found, that is covered by any insurance or not you had on it. While in theory you could go to court to get reimbursed, have you ever tried to sued the federal government? Got news for you - it is very expensive, takes a several years, and your chances of winning is next to zero.

Japan customs is usually pretty gentle with packages they open. They get resealed pretty securely and a note put inside stating they were opened for inspection.

Unless the packaging was substandard in the first place its very unlikely any package would take significant damage from customs inspection.

They open it very carefully in case they decide they want to deliver it and then arrest the recipient.

American customs officers can rip them apart but we can't scratch their nerves of steel.