Napping...is about the most productive thing they could be doing at that point. They certainly demonstrated the energy when the President arrived.
When I was in "A" and "C" Schools in the Navy, I'd be among the first in the class to finish quizzes and exams, and my head would go down on the desk and I'd be out within 30 seconds. I was far from the only one to catch a few minutes sleep. The only time the instructors cared was if we snored loud enough to bother people still taking the test.