Short version of the problem: Parents decide it's time for their child to get a cell phone. They buy the phone, sometimes present it as a gift, and then the child considers it their personal property as, often, do the parents. The child then expects to use it pretty much anytime they wish, any way they wish.
Now, many parents would quickly say that they don't allow their children to use the phone whenever they wish or any way they wish. But, I think parents often set rules in a rather vague way, and then this thing happens which I call "the drift." You start out enforcing the rules, then get lax, and your child, cell phone in hand, is off to the races, so to speak.
And parents are providing cell phones to their kids younger and younger. Parents want their children to be able to reach them for convenience and for safety. (And, of course, parents are buckling under pressure from their children and from other sources.)
But, is an adolescent really able to handle a cell phone responsibly? Some can, perhaps, many can't. I'll be blunt: Very, very few elementary school children are developmentally ready to own a cell phone.
Here's part of the problem: Children and teenagers are more likely to abuse a thing that they regard as their own personal property. If you hand a child a phone and say, "Happy Birthday/Merry Christmas, here's your new cell phone!" your child has every reason to think it's their personal property.
A related idea: Children are less likely to abuse things they borrow from their parents. Hmmm.....
So, here's my suggestion. Consider "easing in" cell phone use.
Now there's an alternate approach to "phasing in," which may seem more reasonable and do-able to some people as smartphones become the rule rather than the exception. A parent could go ahead and acquire a smartphone for the child. For the sake of our discussion, let's say it is an iPhone. I still recommend avoiding giving the child the cell phone as a gift and I still recommend being clear with the child that it is actually the parents' property, which you are, essentially, leasing to the child. It is now possible with iPhones for parents to go into settings, set restrictions on how that phone can be used, and then password protect those settings, with a password the parent knows that is different from the main password. So, a parent could go ahead and let the child have a smartphone but do locked settings that restrict the use. Soon, I'll post links here to directions for how to do that with some smartphones.