Nokia's sound applet does that evil volume adjustment. If you switch to advanced-backlight (everyone should; it has backlight, sound, and (if rotation is installed) screen rotation controls, and the backlight gives full control instead of 5 notches), it won't do that any more.

Nope, I'm wrong, checked and I do still have that adjustment. Maybe this has changed (I suspect multimediad), or maybe I'm just remembering wrong.