Diablo 3 runs active anti-hacking protections, one of them being an agent that hunts for programs running in the background around the game client. Wine, on Linux, is a program that runs in the background around the game client. Wine is also what lets Linux users play games and run software designed for Microsoft Windows systems. This has lead to Blizzard, the company that runs Diablo 3, banning many Linux users. So far, Blizzard has upheld the ban, despite player protests. Ubuntu Vibes has the story.
It looks like not every player using Wine has been banned, but that’s likely more because Blizzard hasn’t gotten around to them, yet. Wine is not a cheating tool, it’s a virtual machine allowing Linux people to run software for an operating system they don’t have to assemble by hand, but it probably would flag Diablo 3’s anti-hacking defenses.
Blizzard has responded, and seems either uninterested, or uninformed, about what Wine is and does.