I think the thought is that it's so they can keep in contact with their parents when they're elsewhere - though I personally just think that's lazy parenting.
I only got my cell because I started driving and my parents wanted me to have something on me in case of emergencies. I hardly ever use the darn thing.
On a tangential note, I'm probably one of the last people in the world who don't have texting. I just don't see the draw of it.