If you are on the phone for educational purposes I think it's okay. If they use it to look up answers, or to call their parents or something why would it not be okay? As for cheating on tests, and gaming that's not very good. School is very boring though.
The silent mode is ok when it comes to cell phones in schools.Some students may have an emergency where they need to keep in touch with parents or other important people and as long as they keep their phone mode on silent then it should not be a disturbance to others.
Mostly, I do not think this is a battle worth fighting. Cell phones have become so ubiquitous and such an important part of our everyday lives, even if a ban were instituted students would not be likely to listen. If the phone is on silent, then the student will only be distracting themselves and affecting their own education, rather than the education of those around them.
Well, phones should be turned off and either be submitted with the school authorities or kept under a jammer zone becoz students nowadays just keep chatting in between the lectures and don't have any attention in the class or the subject taught and then their results come poorer and poorer.
Well I agree nowadays students go to extra classes straight from schools and need to carry mobile phones for their safety but that doesn't mean they misuse the right given to them.