"The two allocate a few moments to check-in on Foursquare or snap a quick picture, but then put their phones away."
This doesn't sound like behaviour of two people who are trying to shun technology; the situation sounds more a akin to a couple of alcoholics who'll look the other way whilst self-medicating.
Agreed, if you feel the need to alert your friends whenever you arrive somewhere, or take a picture to commemorate tonight's dinner, you're definitely in no danger of going off the tech-grid.
People have been managing their intimate/public time like this for decades. I feel like this guy dug up an article out of an old newspaper (or magazine) and replaced some words with "social network".