Studentds must have or mustn't have smart phones?

I think that if you have a smart phone, is because you are responsable with the exams and homework of the school. Have a smart phone is not very bad, with them you can surf the internet, chat with people, play...

I don't agree with the people that when listen something like: "A smart phone is not necessary". The other use the excuse of "It's necessary because if you lost with the smart phone you can call to a friend or normally to your family" , but if you don't have a  smart phone, you can say to the police or say it to some person.

So my conclusion it's very simply, depending of the person you must have a smart phone or not.

Jaume