I am skeptical of any method that moves large amounts of power between two points, potentially through a person. If it's radio, there's the issue of both absorption heating and other biological effects. If it's optical, there's the potential for retina and/or tissue damage. If it's ultrasound, there's the potential for hearing and/or tissue damage.
I think the dream of safely recharging a laptop though the air from something 25 feet away will remain a dream for quite some time. I will, however, be thrilled to be proven wrong.