Did anyone not notice? I mean, if two kids show up at halloween, no matter what kind of incorrect pharses they speak, they would and probably get candy. The fact that only one gets candy and the other one is ignored, implies that she's not being ignored, is that she's a ghost.
Look at the amount of candy, don't you dare tell me everyone in the neighborhood doesn't give candy because a girl can't say "trick or treat".
Wake up. she's a ghost.