As a parent with a child who's learning to drive, I love this idea and I'm teaching it to him.
It's funny how many other things like this exist in the driving world. I remember when my parents were teaching me about "backing up", I was told to put my right arm over the back of the passenger seat. This has a similar effect to the "Dutch Reach" in that it forces your body to look completely behind you, covering blind spots in both back corners so that you can see oncoming pedestrians and bike traffic (as well as cross car traffic) on a sidewalk as you cross it.
It's funny how many other things like this exist in the driving world. I remember when my parents were teaching me about "backing up", I was told to put my right arm over the back of the passenger seat. This has a similar effect to the "Dutch Reach" in that it forces your body to look completely behind you, covering blind spots in both back corners so that you can see oncoming pedestrians and bike traffic (as well as cross car traffic) on a sidewalk as you cross it.