I think the difference is that for *most* people getting chicken on a cheese quesadilla would not have been a really big deal. A mistake, yes... but most people would respond with "Oh gosh, I didn't order chicken. I ordered a cheese quesadilla." Upon realizing there was a mistake, the waiter brought a cheese quesadilla -- problem solved.
To the OP, it's a big deal because it's a "moral issue." I believe the OP expected a bigger compensation (free meal) than the average person would expect, because to her the mistake was a bigger mistake than most people would consider it. I think the "mind reading" thing comes into play, because unless she tells them/told them, I don't think they can be expected to know how big of a deal this is to the OP. To non-vegetarians, this is a little mistake. To her, obviously, it's a big one.
Still though, she ordered something that traditionally doesn't have chicken in it so she didn't have to tell the waiter that she morally objected to chicken when she ordered it because like everyone else (except maybe a few pp's here) wouldn't have expected there to be meat in her cheese entree anyway. She had zero reason to think she had to let them know. Sure she could have said 'I'm replulsed by eating meat so please make sure you don't stuff the cheese quesadilla I ordered with chicken", but honestly why would she bother to since it was a cheese one she ordered and not a chicken one
Now, if it was very common practice for restaurants to offer a cheese quesadilla (without mentioning chicken at all in the dish name of the description) on their menu, yet serve a chicken one, I could see it. But I have never been to a single restaurant where that is the case. So while I disagree with the OP that this was a huge mistake, I don't think she was wrong in expecting just cheese in her quesadilla.
However my ds always gets the cheese or grilled cheese so I can't really count how many times we have ordered them.
of the dish ordered.
. I know, very silly-but, like I said, total cooking ignorance. Hey, I'm not scared to admit it-I'm a total dunce when it comes to cooking!