I had to use the same thing for my college wellness class. The heart monitor just measures your heart rate and transmits it to a stopwatch you wear on your wrist. When you're done, it gives you some basic statistics. If you go more than a few feet away from the monitor, the watch doesn't even pick up the signal any more. They're probably teaching the kids, like me, about how heart rate affects the kind of workout you get. Nothing nefarious here, folks. Move along.
By the way, the strap is made of stretchy material that holds sweat like nobody's business. It's a good thing each student has to buy their own. Even mine was gross by the end of the semester, and I washed it every week.