Hacker News Reader

My old apartment had a system with keys. If you got a package they would lock it in the package mailbox and leave the key in your personal mailbox.

I think that is what above comment is referring to. It is nice having a notification, so don't believe its over engineering.

Again, that's only accessible to USPS and requires a locking box per resident (your mailbox).

Every apartment I have lived has a mailbox. Not only accessible to USPS, anyone can use it.

That is a commonly held falsehood. It is against the law for anything other than postage-paid US mail to be placed in a mailbox.