yes, i know its for security, but technically dont you think kids sometimes have a right to privacy for certain things?
Examples are someone who has medical issues and has a LARGE supply of feminine products they have to carry around in their backpack...
or a kid wants to carry the complete works of byron, or a D&D manual, or something... things guaranteed that you would get picked on or bullied if the local jocks ( im a nerd) saw you with them.
http://www.kbtx.com/content/news/Franklin-ISD-requiring-clear-or-mesh-backpacks-next-year-484869791.html