What Bastille security researcher Marc Newlin discovered was this. If you can send out a wireless signal that pretends to be a wireless mouse, most wireless USB dongles will happily latch onto it -- no questions asked. Then, you can have that fake wireless mouse pretend to be a wireless keyboard -- and start controlling someone else's computer.
With a laptop and a cheap wireless USB antenna called a Crazyradio, Newlin found he could do that from up to 200 meters away. Of course, you can't easily see someone's laptop screen from that far out, but that doesn't mean the hack isn't dangerous. A sequence of keyboard shortcuts is enough to wipe a hard drive -- or open a browser, navigate to a website, download malware and install it on a computer.