I had read about this guys problem a couple months ago right after I made a decision to get a 17". Apparently this guy was one of the first to purchase a 17" Powerbook, and the very first of them were noted to have some sort of hinge/latch problem. I really didn't get all the specifics, but from all the threads I read on this (it made me worry too much because I didn't want it to happen to me), it seemed to be a flaw on both parts. Like Adam said, the button to open it is rather a pain, you need to push it all the way in on both sides and make sure the screen actually pops up. With the hinge maybe being defective, it probably didn't like the way it was being opened and decided to resist.
On a good note, the guy was supposedly able to have his credit card cover the expenses since he paid for it on that. Also, I've had mine since early May, as well as at least 20 other students who ordered them through the university I attend, and no one has had this problem happen to them. Then again, I make damn sure that the screen opens up itself without me forcing it, and I let no one try to open it themselves to be on the safeside.