It should not be because it makes the children infected with the phone too much and could be tempted to go in a way that is not good, and children under the age of 18 years are still in the range early, which may impair learning and lower grades.
It should not make too much stick phone and may be tempted to get in a bad way. And children younger than 18 years old during school age, which may impair learning and academic performance was low.
Should not, because will make the phone too, and might be tempted to in a way that is not good, and the child was lower. 18 years still in school, which may make the studying and learning down.