Yeah, I have a laptop. But none of my classes have any more than 30 students at one time, I'm in small classrooms, and there's no need for me to take my laptop to class. I don't even take my laptop outside my room, I tend to do all my work in my room.
In HS, I couldn't just walk out either. We usually had a police officer outside the parking lot during class hours, so they could get anybody who tried to run away.