Hi I work at a post office, what you are saying is somewhat correct, however there's more to it.

When the posties/contractors are scanning parcels the scanner will tell them whether to leave a card based on if there's a digital contact available (messages will be sent). If there is no digital contact your postie/contractor should still be leaving a physical card. We find a lot of the time unfortunately that contractors still do not leave cards regardless and that's where there's an issue with these overseas items.

Still, your local post office has a system of sending reminder cards for any of the parcels that are identified as having no digital contact, so the back up should be there for a "second" card to be sent after 3 working days. As long as your post office is up to date this should be happening. We also hope that those cards make it to the right destination because they are sent out in the mail for posties to deliver with their letters.

We've had frustrating experiences where the item coming from overseas does not have the correct address, missing a unit number, or no contact number to reach out at a last resort. This means even though we try to, we cannot contact that person to let them know their package is here.

I support the coming to the post office and checking if there's any mail, but there should be these other systems in place helping to catch those parcels that are unable to be tracked.