Earlier quoted context omitted.
It just sends the wrong message. As a company, you are advocating tech that spies on people or in this case the test taker. Overall, it leaves a nasty taste in your mouth that a company would use technology such as this. What else would they be okay with doing once you start working there? Why not do an onsite if you want to make sure of the validity?
Isn't a normal class room in which you take tests while required to be silent and with an instructor/TA/proctor keeping en eye on you very much akin to spying on people? (using people rather than tech, but why is that distinction important?)
I think I'd only consider doing this if I used a computer I could wipe completely before and after. Even then the amount of distrust is off-putting.