1. Should I ban laptops in lecture?
2. Should I make discussion sections mandatory?3. Should I cold-call students during lecture?
In teaching we do things for very few reasons.
a. Because they are inherent in the discipline and academic life. "We're reading Durkheim because he helped to found the discipline." "We'll use APA style because that's what professionals do." "You must offer arguments, not opinions, because in our domain, opinions have no value."
b. Because they are convenient. "We need to get all your papers at once so we can compare them and grade them before the next work is due."
c. Because they adhere to university policies and laws. "No smoking in the back row." "Grades are due on the 11th." "No sexual harassment."
d. Because they embody our values about human freedom and responsibility. "You must take up your own argumentative position." "You may turn in the work late, but it will be marked down." "Write about the one topic on the list that interests you most." Pursue your freedom. Experiment. Explore. Fail. But take on the responsibility of existing and choosing.
(I can't think of many other justifications for why we do this, that or the other in teaching.)
And all of these questions are opened to reasoned debate--because that is one of our values.
Once you say "You will not open your laptops," you are dictating. And you have lost. Now you are a cop, not a teacher.
Practically speaking, I know professors who have had good luck with the "three states": put your laptops away and focus on this (discuss with a peer, whatever); open your laptops and do this specific task; leave your laptop open or put it away--I don't care, just don't distract your neighbor.
2. See "1" above.
Reframe the issue as: What could I learn about making the section worth going to?
Or just put super-important things in section. Sell how great section will be, and then say "of course it's totally optional."