Comment about Violet

It doesn't seem like this has been discussed on here so I'll just post this. In the scene where Linus buys that big box of candy for Miss Othmar, he is walking out the door and Sally sees him with it and mentions to Violet that it is great that Linus is buying that box of candy for her and asks Violet what she can get him. Now here's the thing: Violet knows who the box of candy is for. Why doesn't she tell Sally, "Hate to disappoint you, but that ain't for you. It is for the teacher Miss Othmar."? Instead she makes the comment about the shaving lotion she got for her teacher. Did she just feel, "Aw, let her find out the hard way. After all, she is that blockhead's sister."? Anybody wonder about this?