You are wise to consider a theoretical risk like this, however, with all the
people using streaming audio, and all the viruses out there (63,000 to date,
according to McAfee) this has not happened. The perpetrator would, at the
very least, have to be in control of the computer sending the audio. If they
were to send out a virus, there would be a lot of angry folks all at once,
and the offending machine would be traced and soon stopped from transmitting
on the Web. Then, the authorities would track them down. No hacker would
bother with this, as there is too little bang for the buck. It would be like
grabbing a Rembrandt and running out of the museum, or taking a pot-shot at
the President. Was the brief period before capture really worth it?