I've been around long enough to see smartphones take off, and still have almost no interest in them at all. I don't use much social media at all, since it's kinda just mostly more stress inducing anyways. It's just funny and also depressing, to see someone stuck with their nose to the screen.. to the point they ignore signals and more. If you're that addicted to your phone, you seriously should be taken to some sort of rehab.
To the story though it's interesting, to know the actual issues many people experience. Anyone commenting about the whole "phone from 2005" thing, really needs to understand not everyone needs to be connected 24/7 to Facebook, Twitter, etc. You're more engrossed with online activity, when you should be aware of your own surroundings.
I wonder how many you could trip, simply because they get so engrossed in their phone. Probably a lot and it would be a clear reminder, to stop being so worried about the small things. Actually be aware of other things, than something probably not even important at the moment. I'd imagine many would do it, to be a jerk simply because they can.
Better yet just have a sliding "wall" that you can move, see if those too busy to notice actually walk into it. If it happens enough, they might actually smarten up a bit. Then again I see smartphones often reducing attentiveness, and overall IQ at this rate when they can't stop to experience life.