The entire purpose of the DRM architecture is to prevent illegal copying and playback of purchased content. However, devoted music pirates don't even need to worry about this barrier because there are other illegal, peer-to-peer options that allow users to download MP3 files for free with no DRM restrictions attached to them.
Additionally, users can burn CDs from most online music stores and rip the tracks back onto a computer to get rid of the DRM restrictions. The fact is that sticking a digital tag to a purchased music file does very little to prevent music piracy and is mainly something for the content providers to use to maintain exclusivity for their platform.