I saw this article a few days ago and thought I'd bring it up.
DS Lites experiencing a crack epidemic?
They have stated the following in the article...
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">According to several Internet-savvy DS Lite owners, the left hinge that connects the unit's two screens is prone to cracking.
Photographic evidence of the small crack, which is a few centimeters in length, has turned up on several Internet sites, with users explaining that their dual-screened darlings just aren't what they used to be. It should be noted that the crack is merely aesthetic and does not affect the unit or gameplay.
Of course it's the loudest voices that are heard on the Internet, and they usually belong to those with gripes, so the extent of the crack epidemic isn't clear. A quick poll of DS Lite-owning GameSpot employees yielded no such broken units, but reports of more cracks are popping up on message boards.
They also state later that...
GameSpot contacted Nintendo customer support, who explained that this malady doesn't seem to be what the company calls a "known issue" and appears to affect less than 1 percent of DS Lites. However, unless the broken hinge impairs the opening and closing of the clamshell portable or the overall stability of the top screen, it does not fall under warranty. A damaged unit could be fixed for $50, down from the normal rate of $75. </div></BLOCKQUOTE>
Like the article says, this may never happen to your DS Lite. Though it sounds as if, with the mass production of the DS Lite. It is a possibility.
I know I open my DS Lite up, the full 180 degrees and it has yet to be a problem...