Agree fully with j_t.
Making assumptions about what the aircraft limitations imply, without explicit statement, is nonsense. Just because something doesn't NEED to be on, does not imply that it MUST be turned off.
Most importantly, if the Operating Manual/Checklist doesn't dictate an action (as significant as disengaging an aircraft system), it should not be done.
Miles - you can rest assured that unless the manufacturer says it MUST be turned off, the aircraft was certified with it turned on.
Most of us are pilots, not TEST PILOTS. Follow the procedures in your Operating Manual unless you feel like becoming a test pilot!!
VI