if disarmed is == 0 (= off) the ramp will be without effect. If someone on a fixed wing set a disarmed PWM (e.g. for the ESC) it will be obeyed, IFF it is lower than the min PWM. What is not possible is a 1500 PWM for servos on fixed wing. But I do not see the benefit there, and its kind of dangerous for non-servo actuators, depending on their throttle safety. I see no benefit in having a disarmed PWM that is not low.