Circular reasoning. That's like saying it's impossible for a gun ban to affect law-abiding people, since anyone with a gun in violation of the ban is by definition a criminal.
"Circular reasoning"
The circle can be traversed in either direction. Restricting activity at a school lunch stifles the student's independance, affecting their creativity, and ultimately leading to a generation of pathetic zombie-like drones. So, never restrict any child from doing anything.