In a way, I would consider this not-quite a virus. I mean, any malicious code would be interpreted code, that is, actions taken by the playing program. It's not executable, and so long as people don't design IRRESPONSIBLE programs (*cough* Microsoft *cough*), it will be a non-issue. I mean, this is just as deadly as warning about viruses in text files, or macro viruses, or viruses in pictures. So long as the interpreting software is not made with handy-dangle-standard-breaking features which are ill-thought out and un-necessary, it won't be so much of a problem.