When I was in school, I feared to become a scape goat and acts like a good school girl. The use of phones is not something new among students because we rely so much on Google to come to our aid. Your lecturer even had the time to pass your work through plagiarism detector, in my school, you'd see your papers lying on the floor, scattered and most of them ended up at the akara seller woman and we would just be given random scores. While some schools take these stuff seriously, others won't. But the best is to enforce some rules as regards these devices because it's not possible to ban them.
Akara seller will always have steady paper supply. Haha.
Maybe rules will work. But they'll also be new rules to break and more problems. You know students...