naive perhaps, though would it be possible to transmit such 'radio code' via a small transmitter, say at short range in another building, that could send a stream of infecting code into a building (and thus the infection could begin outside the USB framework), such as via a small programmed microcontroller with radio antenna, either networked or running autonomously (or would this be a pirate radio issue, closed-in on quickly by HAMs monitoring misuse of spectrum). further, if this radio broadcast of code were possible, one-way or bidirectional, what would prevent this from scaling city or region wide if a transmitter were overtaken and sending out signals to computers en masse, to reprogram firmware, targeting via equipment statistics or OS/hardware demographics. just wondering if software-defined radio may be a context for hacking computers beyond the peripherals directly attached to the computers, such that a different security situation, boundary, or perimeter may exist yet not be accounted for or protected against.