From your blog:
> Finally, here's what drove the purchase: I was taking a long car trip, and my wife was doing the DJ work using my device. Of course, every time she wanted to change tracks I had to unlock the device with my fingerprint. Ridiculous. This little device solved that problem
Wouldn't telling her your phone's code, or temporarily adding one of her fingerprints to it for the duration of the journey, have been a much simpler solution...?