Yes, its almost a feeling of exasperation, something usually used in a situation where the outcome was predictable but the speaker was hoping for better luck or some different outcome. In your case, Tintin had hoped the individual would be there but isn't surprised he's gone. But nonetheless, he's quite frustrated.
(person 1 who likes cake): I think I'm going to have, hmmm, some cake for dessert.
(person 2 who knows person 1 likes cake): You would order the cake.
--->You WOULD eat cake because you love it and you can't help yourself and everytime we go out you're always eating cake, will you ever eat anything else?? >_<
During speech the intonation is what makes the phrase special. If you add an interrogative lift to it, going up, it becomes a question. (You would?) If you add a flat and somewhat irritated intonation to it, (you WOULD eat cake..>_<) then the nuance is clearer.