[CaliforniaKarl]

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

[cogman10]

What's the reason for this? Is the post office locked up on Saturday?

I'd expect 2 drop boxes near the same location would naturally be picked up at the same time.

[hinkley]

Delivering the mail to a drop box is a task often done under duress. This is the same reason we in software have Five Why’s. Someone sitting calmly outside of the problem will always find a way to blame the victim for not reading the instructions. That doesn’t absolve the builders from their share of the guilt.