[CaliforniaKarl]

That kindof makes sense to me: If I drop something into a post office’s mail box (outside or inside) after the day’s last pickup, even if the mail is inside the post office, it’s not going to be touched by USPS hands until the next day that the post office is open.

This can be tricky. For example, at the Stanford post office, the drop boxes outside the post office have Saturday pickup times, but the ones inside the building do not (the signs inside warn about this).

[weinzierl]

In the past this used to be handled explicitly: courts, tax offices, municipal administrations, and patent or trademark offices had special mailboxes whose internal compartment switched every hour. That way, the time of deposit itself was objectively recorded and legally relevant, even outside office hours.

The same kind of mailbox was sometimes used for bid submissions in tenders, to prove whether an offer was submitted before or after the deadline.

[hinkley]

> For example, at the Stanford post office, the drop boxes outside the post office have Saturday pickup times, but the ones inside the building do not (the signs inside warn about this).

That’s counterintuitive though. I can see why people miss the sign.

[dylan604]

not familiar with the specific PO at Stanford, but I'm assuming the "ones outside" are the traditional drive up blue boxes that are also emptied/collected from the outside. I could see having these picked up by a truck on the way to a regional office without having the driver also need keys to collect from a location that is not open at the time of collection.

[CaliforniaKarl]

If I remember correctly, the sign is located above the sign that lists the pickup hours for the inside drop box.