As a former economics professor, I did exactly the same thing these authors were suggesting. While some students did use their technology effectively, the vast majority of whom were just distracted, not to mention probably taking far worse notes.

One small story, I was teaching a class during March one year and I had a student obviously not paying attention. Then, all of a sudden, this student's hands went in the air and an audible "Yes!" came out. I then asked him if there was something important - "Kentucky just won in a buzzer beater!" The vividness of this memory and the difficulty I had in containing my rage is still at the forefront of my mind.

For me, the impact was that while students should be able to do what they want for the most effective solution, it becomes a problem when activities disrupt the learning of the students around them. Someone not paying attention and watching cat videos is infectious as there is a lower percentage of participation and others start to watch the offending student's screen.

My perspective is (although unproven) is that the real reason laptops don't work is because of the temptation to do something else, not necessarily because of the medium.