My initial knee-jerk reaction would be to object to kids having cell phones. But then I remember my teenage days and it seemed the phone was attached to my ear. And in my parents' day, the phones in the corner candy stores were quite busy.
However, this was when I was in high school, not elementary school.
I'm not so thrilled about the idea of "tweens" or younger kids having cell phones. (A friend gave his 9-year-old one last Christmas.)
Of course, these days kids are far more isolated than we were. We were in the city or more built-up suburbs where there were plenty of friends within walking distance. Today kids have to be driven to practically any kind of activity otherwise they're isolated. (Also parents want more control over their kids than ours did.)