Cell phones in the classroom?

Do most elementary school students even have cell phones? This is the question that kept coming back to me during class today. I thought there were many good points being made about the uses of technology in the classroom; however, I felt like the points being made, while very useful for secondary education, had little practical application to elementary. This could easily be explained by the fact that I simply do not know if the 3rd graders I will be working with will have their own phones. I can see the immense value of integrating technology into classrooms and today really helped to highlight some ways we can use technology well. I particularly liked Flipgrid and the ideas of how to use it for homework. Flipgrid has some similarities to Seesaw, which we are using in a different class, and I have found both to be good ways to interact with the material, my classmates, and the teachers. Bringing this back to my main question, if my 3rd graders have their own phones should they be allowed to use them in class or should they leave them in their backpacks? To me it seems that at this age they shouldn't have access to their phones at all times. In the classroom they should be present and working with their peers and engaged in the things happening around them. That isn't to say that online interactions aren't good interactions, it just seems that developmentally they shouldn't always be "plugged in". If it is the parent who is wanting their kid to always have their phone, I think I would encourage them to loosen their grip on their child and call the school or call, text, or email, their child's teacher if they need to reach their kids. This would help to give the kids a little more freedom at school without being worried that their parent may call them at any second. This is all just musings based on little information though. I'm thinking that there is much more for me to learn and some of it I will learn on the job. I know I have personal opinions on who should and shouldn't have cell phones, but I also know we are in an ever changing world of technology and I need to stay flexible and keep up with the times.