For her duplicity in getting Sarah to call off her engagement to Danny, Princess Fiona could have been charged with interfering with the proper succession of a monarch and could, therefore, have been committing treason.
Near the end of the movie, Sara sends her class to recess 5 minutes early and does not go with them. There is not a teacher who would do this as the students would be unsupervised. Even if there was some sort of recess monitor, she sent them early. So they would still be without an adult for a time. Leaving students unsupervised would get a teacher reprimanded, in the very least. Sara seems like a competent teacher and she likely would know better than this.