Hold up one sec.
First off, I hate black boxes. They're a slippery slope from just youngsters having them voluntarily, to be being forced to have them, to everyone being forced to have them.
Secondly, you're getting dangerously close to fraud on the second driver thing. I agree, adding one can help reduce the cost, however just be careful that you actually know the person and that they truly do do the job you say they do.