Earlier this week I flew back to Washington Dulles from Memphis via Chicago. Familiar story: short change, airplanes right next to each other, luggage transferred via central routing came on a later 'plane. The courteous assistant looked up my baggage details and led me to an entry terminal. He asked me to select the "OK to deliver by overnight service", which I did.
9:30 I get a call asking if it's OK to leave it tonight. I say "sure" and attach a signed note to the door asking the delivery service to leave the bag on the stoop.
Next morning I wake up and the bag is on the stoop. I've complained in the past when they've got it wrong.
So, this time, United, well done.