Yonder pouches for High Schools

I am a high school special ed. teacher at a large urban high school. In January we are making the kids use yonder pouches for their cell phones in order to create a cell phone free environment. Our union chapter leader toured another school that did the same and felt that the initiative might work given enough manpower early enough to enforce compliance that it could work. I remain skeptical, however, and I wanted to hear from any other teachers who works at a school that employed the yonder pouches in an effort to create a phone free environment. Did the initiative work at your school? What were the challenges or benefits in the classroom of the initiative? Would you recommend other schools trying it?