”- - the scientists suggested this technology could be scaled up to power Internet of Things (IoT) devices and sensors using a small proportion of the excess radiofrequency (RF) signals they use to communicate with one another.”

So, we could get wirelessly powered sensors and scatter them everywhere. What could go wrong. Literally nothing. There can never be any privacy implications, since it’s well known that people using those sensors and IoT devices are physically incapable of having bad intentions.