Invasive
To play a copy-protected Sony CD on your computer, you must use their proprietary media player, which installs itself from the disc. In the process, it covertly inserts a rootkit, a package of hidden files, in your Windows system. This software hogs system resources even when not in use, is difficult to detect, can’t be easily uninstalled, and may disable your CD drive if you attempt to delete its files.
Ah, the music industry, still hard at work discrediting the legitimacy of copyright protection…
Sony, Rootkits and Digital Rights Management Gone Too Far [Mark's Sysinternals Blog], via Download Squad.