One of the things about battle.net though was that pirated StarCraft copies couldn't connect to it. Battle.net thus served as an "effective" copyright protectio

One of the things about battle.net though was that pirated StarCraft copies couldn't connect to it. Battle.net thus served as an "effective" copyright protection device -- circumvention of which is illegal under the DMCA. This has been tested in court, and the court found in favor of Blizzard. So yes, a judge has ruled that reversing the Battle.net protocol is a DMCA violation. That's why the bnetd.org domain was awarded to Blizzard (though a US court could not prevent the distribution of bnetd outside the USA).