How can I kindly explain to the librarian that she doesn't need to be eating McDonalds?

The people in this section are so boring, I say revenge against this hypocritical librarian is way more important than studying. Although I think my advise is a bit late, I would have taken her McDonalds and told her she's not supposed to eat in the library and told her she does not need the calories anyway. But I'm pretty sure that would have got you kicked out.