I aspire to "be in the moment" as well, but being an INTJ I live in my head almost all of the time.
If Stogdill is spending his time daydreaming or thinking about other things (I do this as well) then ignoring his phone is not helping him live in the present anyways.
You aren't the first to mention that, and it's a good point. But I am not just day dreaming when I'm not looking at my phone or whatever. I spend a lot more time with people these days, and I'm loathe to pick the damned thing up when I'm with them.
If Stogdill is spending his time daydreaming or thinking about other things (I do this as well) then ignoring his phone is not helping him live in the present anyways.