That buying part is really important for NOD32. Major people use pirated versions of NOD32 and these pirated version update the virus signatures from the trial servers, not the retail servers. Hence the detection rate is poor in pirated versions of NOD32. U can even find it for yourself. After installing the pirated version, when u try to update, the programs downloads the trial detection engine and replaces the core NOD32 files with this trial engine.
Yep correct, comes to show that security doesn't come cheap::redface: