Got a response back. Not impressed with it and I responded so. My response was as follows: 

I understand your reasoning but find it highly disheartening that the main reason this policy is in place is because of the bad decisions of others and therefore the rule following kids have to suffer. And yes my daughters have carried binders but when they are as small as my girls, it is incredibly unhealthy to have all that weight on one shoulder. Think a 10 lb bag on the shoulder of a 56 lb child for the six hour day going up and down stairs between every class because every semester that’s how my girls’ schedules have been. 
If we are worried about hiding things, offer to let them use clear backpacks. If there’s no room in the classrooms, maybe we need to look at the size of our classes and classrooms. Because let’s be honest, zipper binders are the same size as backpacks. 
Let’s fight FOR our kids, not against them. 

Terri Waters