Fair enough, but counterpoint: I live in a vintage building on a busy street, and the USPS carriers never leave packages on our doorstep. Each apartment has put up a little sign on their front door indicating how they'd prefer packages left (on the stairs, out back, whatever), which the postal workers all adhere to.

I see them walking past my window, from the front of the building to the back, all the time.

So they must have some flexibility...