A few months ago it almost happened to me. It was horrible. I was traumatized. I wonder, how can that happend in 2011? why me? why to my laptop?
It was a worm afternoon in Madrid, the meeting I attended was so intensive I didn't get to login into the KDE Plasma Workspace session but instead I let the laptop on the KDM login page. Once the session finished I closed my laptop and put it in my bag full of battery.
I'm not sure about the amount of time, but probably between 3 to 4 hours later I arrived home, opened my backpack and there it was, I found my laptop burning, hot as hell I even had to grab a cloth to open the lid and move the laptop to some place cool. From that day my new battery went form 98% of capacity to 90.
That night, I sent an email to some KDE mailist asking for this issue, until today nothing has been done to fix it.
I don't want anybody to pass from the same I went through, that's why now with lightdm-kde the computer will suspend if the lid is closed.
Next thing I want to do is show the battery remaining somewhere and suspend the computer after 2 minutes of idle time.
With that, lightdm-kde will have great power management support.