In all honesty, gazing at the packaging of this so-called Diablo III, it seems implied that a few users will die while playing. Via the Australian:
The Taiwanese teenager collapsed and died at an internet cafe after playing Diablo 3, a popular online video game, for 40 consecutive hours, according to Australian Associated Press. The 18-year-old identified by only his surname, Chuang, booked a private room at the cafe in Tainan around noon on July 13 and played for nearly two days without eating.
On the morning of July 15, an attendant entered the room and found Chuang resting on a table. After the attendant woke him, he stood, took a few steps and then collapsed, the report said. He was pronounced dead shortly after arriving at a local hospital.
In February, heart failure was the attributed cause of the reported death of a man in New Taipei who was found dead, slumped in a chair facing a computer with his arms still reaching out for the keyboard after playing for 23 hours.