oh boy...
It seems I should explain myself to those who have no idea what they are talking about. In semester 1, week 1 of law school, the elements of a negligence case are laid out. They are the following: duty of care, breach of duty of care, cause, proximate cause and damages. I will explain the possibilities.
Duty: Nintendo owes a duty that its product will not harm its consumers.
Breach: If Nintendo failed to recognize that the motions encouraged by high scores in its video games could cause damages to the user via a failure of the engineering of the Wii-mote then there is a breach of duty.
Cause: If Nintendo's breach caused harm to the user
Proximate cause: If Nintendo's breach resulted in the damage of the user, specifically that the arm is injured by the movements encouraged by the achievement of high scores with the Wii system.
Damages: There is permanent damage to the user
If all of these elements are met, then you have a case. If not, then you don't have a case. But the lay-persons' knee-jerk contentions that you are somehow a moron for injuring yourself by using the Wii are not necessarily correct. Further, I don't think that I am a bonefied (whatever this made up word is supposed to mean) idiot for suggesting that you MAY be a victim here. Understand, these are the same people that got pissed when that woman won a judgment against McDonald's for burning herself with her coffee. They say "aww, ridiculous! coffee is supposed to be hot!" They ignore the fact that the coffee was 200 degrees and the lid was not secured, and as a result there were 3rd degree burns. There are a lot of things that add to your case or detract from it, but to say that you assumed this risk was there is simply incorrect.
Furthermore, the fact that the manual etc says "yeah, if you hurt yourself with our product we're not liable" is completely irrelevant. I can prove it. Next time you are at Disney World or Six Flags or something, check the back of your ticket. It will say basically the same thing. I assure you, however, that if you are on thunder mountain and the track is rusted out, causing you to rocket off the track and become a paraplegic, you will be entitled to a settlement. It has nothing to do with "common sense" or different circumstances, but everything to do with the elements listed above. Now I don't know if you have a case. But this should not be simply discarded as preposterous nor should you be labeled a "bonefied" idiot.
If the elements are met, you win.