Diablo III players? Those affected say yes; Blizzard says no.
Players who were using a program called Wine to run Windows applications on Linux machines flocked to the Diablo III forums to report that they were finding their accounts banned. "I got banned last night as well," one player wrote. "Other than running under Wine, I can't imagine why. Level 30ish char and not so much as a gaming keyboard."
A Blizzard CM said that the studio investigated the claims and found that this wasn't the case: "We've extensively tested for false positive situations, including replicating system setups for those who have posted claiming they were banned unfairly. We've not found any situations that could produce a false positive, have found that the circumstances for which they were banned were clear and accurate, and we are extremely confident in our findings. Playing the game on Linux, although not officially supported, will not get you banned -- cheating will."
[Thanks to greaterdivinity for the tip!]