A while back I wrote about Blizzard's suit against MDY, which produces
a WoW bot called Glider. Blizzard sued MDY and the judge in the
case just ruled that MDY violated the DMCA. (Ars Technica article here;
ruling here,
link thanks to Joseph
Calandrino). I'm not a lawyer but as far as I can tell from reading the ruling,
the reasoning is that the visual and audio elements that emerge from
the act of playing WoW constitute a copyrighted work, the warden (WoW's anti-bot measure)
controls access to that copyrighted work, and Glider allows you to circumvent that
access control, hence it violates the DMCA anti-circumvention provisions.
It's interesting to ask how far you could extend this reasoning. Consider this alternate design for a WoW bot: you run WoW in a VM and then have your bot interact with the VM to scrape the screen, simulate key and mouse presses, etc. [This was originally suggested to me by Terence Spies.] The warden can't detect your bot because it's shielded by the VM (it might detect the VM, but there are legitimate reasons to run WoW in a VM). The VM itself isn't a DMCA violation because it has significant legitimate uses. The bot doesn't have to specifically have any anticircumvention measures to avoid the warden; it just processes the video output and simulates user input. Would the same reasoning still apply in this case?
I read the complete ruling a couple of days ago and had exactly the same thought. It seemed like the case turned on the technical circumvention measures. So the more truly you could simulate a human player, the more likely you were to be in the clear.