I have some Idea that may help and save alot of multicopters from crash,I call it Altitude Floor; the idea is to create an imaginary altitude floor(predefined) for example from ground level up to 5ft activated by AUX switch.
The pilot can fly like crazy above that floor,once the multirotor will hit altitude floor zone the FC will take the controls and will level the multicopter and by predefined time/altitude the controls will return to the pilot.
Of course you have to have a baro and silly pilot

Is it possible?