I would guess all take-off configuration warning systems are purposely designed in a way they can be overridden, simply because there are some phases of flight where a false warning might be even dangerous. These situations include the take-off run past V1, i.e. the speed above which the take-off must not be aborted even in case of malfunctions, such as an engine failure or fire, or touch-and-go landings.
Last edited by hvogt; 30th Mar 2013 at 18:59.