This to me smacks of fear and really some perverse form of protectionism. The whole idea of "schooling" is built upon the premise that there is some fundamental set of knowledge that it's important for students to master before they can function in the world. However, with the advent of computers, the internet, and their miniaturization in the form of smart phones, any piece of human knowledge is instantly retrievable and usable.

What's the point of a semester long instruction in algebra or geometry still filled (mostly) with rote memorization of methods and formulas when those methods and formulas are available ubiquitously at the touch of a button. Schools see smartphones as an existential threat and rather than try to adapt their model of instruction to the tools that we all now have, they're attempting to ban them outright. I only see this leading to resentment and anger from students who are accustomed to instant, easy access to information.