I bet she hid some pencils and books and maybe a snack in there too. What idiots those police were, to just let her walk.
By the way, the length of the scissors is irrelevant. It is the design of the blade that makes it suitable or unsuitable for use as a weapon, and most common scissors these days are useless for stabbing.
When I was in school (yes, it was a while ago) a girl tried to stab a teacher with a pencil. Will pens and pencils now be considered potential weapons? What's left after that-crayons?