I think she went to test it on her own with the professor and it worked fine. Then again testing these things in class where there are 30 or 50 students isn't the same thing as testing it in an empty room where your standing next to the professor testing it out.
I'd be willing to bet money that if modified you could probably cheat for someone else using this device.... Modify it to send out a signal for not 1 but two people. The device simply has to transmit a signal at the time of the proper answer. So if you modified your device to send a signal for you and a friend and you were the one with the majority of the answers, you could be all the way across the room from each other and it would be difficult to say you cheated from one another. You then answer things to the best of your knowledge and your idiot friend gets the same grade as you. He/She stands there and clicks away like they are actually taking the test
I'm interested to see if this would be possible or if there are other checks and balances that professors use to counter this sort of idea on cheating.
Keep in mind I'm not suggesting anyone do this, or that I myself would do it. I'm simply posting this out of interest in the technology itself.