Many newer drives have this region code change restriction built-in, some has it a an option (for computers that check for this option set - probably Sony Computers...) - and some (older, many Asian) have no restrictions.

HD621, G98DH, G68ADV, Bc Acoustiqe ACT A3, 5200C DSP33, NuForce Reference 9 monoblocks, 2x SB3's, Velodyne DD-15 & DD-12 Subwoofers and a Meridian sub.