Sony is in the news with its latest anti-music piracy tactic. Its new copy-protection feature, designed to prevent production of MP3 and MiniDisc copies of CDs, can be disabled with an extremely complex, hi-tech device called a felt-tip pen. Reports say drawing a line round the edge of a CD disables the dummy track designed to fool computers. But you may want to think twice about fiddling around with protected discs because some users have experienced problems, ranging from disabled CD drives to disabled machines, after trying to play Sony copy-protected discs on their computers. If you buy a CD labelled 'not for PC or Macintosh' you would be wise not to test the claim.