Tonight i was hacking on my ibook on my sofa watching Extreme Makeover. Then "peeeeeeeeeeeewwwwwwwwwwwww". No more battery.
I haven't received any warning at all. Maybe gnome-power-manager is a bit broken currently on Debian/sid because of hal/s2ram/whatever on ppc. I mean s2ram and hal works, but no the way gpm likes them too (i have to manually run s2ram to suspend). But at least , I would have expected gpm to warn me, and then shutdown my laptop. Yep, i've checked, when the battery level becomes critical, it should have poweroff. But that did not happen.
Now i only trust the battery gauge LEDs.
Happy End: thanks to reiserfs and emacs, i haven't lost a single line of code :)