I think Anon E Mus hits it on the head. And, contrary to a few comments, I don't see young people getting a phone as parental neglect or abuse or whatever, not saying it's a great thing but it sounds to me like those people in the 1950s that said Rock and Roll was corrupting our youth, and so on. It's a societal change and you can either fight it or go with it.
Food for thought, if you read some of Victor Vinge's writings on the technological singularity, he sees the possible methods of some super-human intelligence emerging as being:
1) Computer becomes self-aware and gains super-human intelligence.
2) Computer netwrok (and possibly associated users) does the same.
3) Computer/human interface becomes so intimate the user can be considered superhumanly intelligent.
4) Biological upgrades.
Obviously, Facebook updates and tweeting are not helping anyone's intelligence. But it appears to me things are moving very much towards #3, at least in terms of people being able to stay in communications; I see people fire off and read texts almost subconsciously, they can literally keep up a verbal conversation while they are having a text conversation with someone else. This seems for some much less like them typing and reading an external device, and more like the device is a direct extension of their consciousness. Even with those awful touch screen keyboards haha.
I could see it being unnerving to have this taken away, it's almost like saying you are going to remove someone's sense of hearing or touch for a day to see how they like it.
So, a couple of my cousins have this bad (they're about 10 years younger than me.) It's like
(One of my uncles): "We're going to the retirement home to visit your great aunt, she's not in good health so we're seeing her while we can."
Them: "OK." *tap* *tap*
Me, I say real casually... "Oh, umm... when I was there a few days ago, there was not cell phone service, the mountain blocks the signal."
Them: "Umm, what? Really?" *TAPTAPTAPTAPTAP* (they both looked a bit startled, and started texting like madmen, I think warning everyone they'd be out of contact for a good half hour or hour.) They managed not to get the shakes for that hour or so. When we got back in service, it sounded like their phones were going to explode from dozens of queued texts shooting into them.