Funny thing about many rich people, they like to see themselves still down to earth and as realists, but then again they still send their children to "good" schools, buy houses in exclusive parts of towns, aso. Most of it makes sense, as being rich, makes you a target. "Your own money is something you possess. You don't talk about it!" Everyone wants to offer their children the best prospects for their future, -> "better schools". They want their children to marry into other rich families, as anyone else just has to be out there for their money (sadly often enough true, yet not a morally justifiable reason to always assume it). Yet at this point they themselves also acknowledge, that there is some differences between them and others. And those people start to see dangers, that are alright to take for everyone else. Therefore I believe (and also saw), that not few rich people picked up behaviors, that really, reeeally remind me of aristocrats. Many people with money do distinguish between classes. But poor people do so, too. XD
Now taking the above into account in regards to this chapter: People, that go out on a regular basis to eat in such an "establishment", certainly do have their "standards". This is not something your regular well off merchant or attorney would do, except on special occasions. Therefore that waiters reaction to those dragon-kidney-stones didn't make any sense. You don't accept 150 GC, if you lose out on 1000GCs later on.