Yes, I should have been more specific and said "two ducks!" - but then they also should have asked (they didn't).
So we eat the food, and eagerly await our duck, and one duck's worth of duck arrives. And it's delicious. It's amazing. It's juicy and fatty without being greasy. The plum sauce is truly memorable. Everything is fresh. It's tender. It's better than Celestial and much better than Wei Fu Lou. I ask for more duck.
There is no more duck, because "you only ordered one duck when you reserved."
"You didn't ask and I thought you guys were true professionals and should be able to handle this sort of thing."
"When a table makes a reservation, we always give them one duck unless they ask for more. You should know that."
"The boss isn't here." (Either she was lying through her teeth - which is quite likely - or the owner of the place never actually visits and lives off the profits in some hideous granite and marble monstrosity on Ren'ai Road, which I concede is also likely.)