[derefr]

Every day when I pass through the lobby of my apartment building, I think about the fact that our lettermail gets locked up tight in individually-keyed mailboxes, but — due to our building not being "large enough to qualify" for a parcel dropbox — large high-value parcels instead just get left lying on the lobby floor beside the mailboxes, with the matter of not stealing other people's parcels left entirely up to the honor system. (And yes, this is the same lobby that arbitrary guests will walk through to the elevator if buzzed in by any tenant who hears the word "Amazon" muttered vaguely through their phone.)

Of course, the locks of those individually-keyed mailboxes are also probably rakeable or bumpable or some other two-second attack. But at least that deters people who never bothered to look into how locks work.

[lmm]

A parcel is almost certainly replaceable stuff. A personal letter could be something like a passport or birth certificate or bearer bond.

[derefr]

Here (Canada), "passports, birth certificates, bearer bonds", etc. all get sent as registered mail with receiver identification required for release — which means they get held at the nearest post office for you to go pick up, rather than coming to your mailbox. (Instead, a notice card gets delivered to your mailbox, telling you to go get the thing.) Surprised that's not a thing in the US(?). Is that why long-term identity fraud is so common there? Birth certificates and other legitimate primary identity documents just being stuffed into insecure outdoor mailboxes where anyone could grab them?

Also, while many parcels are just purchases from companies, a parcel could very well be a priceless heirloom sent by a relative. Or, say, a live reptile.

The postal system bakes old assumptions into it, where ordering goods for delivery didn't used to be nearly so common, so a much larger fraction of parcels used to be of this personal variety. Which makes it even more curious that they're generally handled in such a blasé manner.

My only guess is that shipping parcels is expensive by itself, so almost nobody bothers to pay double to have their parcel handled securely as registered mail.

[iudqnolq]

I can tell you from experience that a California birth certificate isn't mailed folded and is much too large to fit in one of those postboxes.

[lmm]

Shrug, my birth certificate was folded and fits in a normal letter envelope, so does my grandfather's from another country.