well this is an interesting fact showing that Larian is a company who think first about their players and then about profits, unlike most of the company in video game area...
DRM is a real shit whatever form it takes :
a compulsory connection to play
use the DVD every time you play scratching it
kill the reuse market and lending impossible
and as said, company justify it by the fact that it protect their games and they can sell more well actually the only game which I know was not properly hacked was Diablo 3...