My intention for the original post was to shed some light on warm up routines, as my suspicion was that most "rec runners" were doing this 'no-stopping' thing out of either compulsion - or because no one had told them any different (maybe they'd run in HS or never had a coach).
If people are time poor, it's understandable that they'd go straight into their workout; though I still think even a 30 sec stop allows your body to somewhat reset and prepare for the huge jump in effort.
I'm not exactly sure on the science (though I've heard Marius Bakken talk a little bit on this topic), but from my experience, starting a workout "fresh" (without jogging straight in from the warm up) allows me to hit much higher intensities, at a much lower perceived effort.
Therefore, if anyone has been unwittingly doing their workouts without stopping (because they didn't know any different), try it. Maybe do a few strides as well (with a walk back recovery), and then start your workout. I guarantee it will be a much higher quality session.
P.S. For those people asking "how do you know they don't?"
It's really, really easy to see the difference between a person's elapsed time and their moving time on Strava. Those are literally 2 of only 4 stats that pop up in the main stat box when you click into a workout on the web version.
And, If someone were to do drills and strides (properly) without stopping their watch, they'd have some very wonky km/mile splits before starting their workout.