You know standby mode, with ol' WiiConnect24? It gets quite hot. So hot that the GPU is cooked medium-rare. Symptoms include random dots appearing on screen, both in games and on the Wii Menu. They're mostly black or white, flash or flicker, and it gets worse when you're in a game (They're everywhere in Zelda). Note: http://boards.thewiire.com/index.php?showtopic=18093
Potentially, although it might be a design flaw that'll affect it after a long sesh anyway. Though it shouldn't as in standby mode the fan stays off (probably why it's overheated) You can keep WiiConnect24 on, just turn off standby connection.