More than a year ago, my friend Brad Shuler gave me a strip of paper with some little bits of some kind of plastic on them. He told me they were to keep my 15" PowerBook G4 from having its lid pop open while in a backpack or shoulder bag. When this happens, the machine can come out of sleep and end up draining it's battery completely.
The idea behind these little do-dads (called Wildeepz by their maker) is to bridge the small gap between the screen and the rest of the laptop when the laptop is closed. By creating positive pressure, as slight as it may be, they keep the lid lock engaged and prevent the lid from popping open and waking the laptop.
I had completely forgotten Brad gave them to me, and it hadn't been an issue until I recently got a Mac Book Pro of the 17" variety. Then I had my first drained battery the other day, and my conversations with Brad came rushing back. I still didn't remember he'd given me some of them, so I was debating whether to spend the $17 for the ones from Radtech or try to find some equivalent. Much to my surprise, I was organizing all my computer boxes and gear (a long-delayed task) and found the little strip of Wildeepz. Two little do-dads later and my 17" MBP is protected from unintended wakups and drained batteries.