Saying its 'fail safe' actually makes me wonder how it works in detail, like would it require a sonar reading? Phantom 3 standard doesnt have sonar, or does it? Im just thinking of how this could go wrong: imagine you're in a strong updraft / thermal, and you pull the throttle stick to descend. But because of the updraft that just happens to match your descend rate, your actual altitude remains steady and the phantom thinks its landed ? Far fetched, I'll admit, but it does make me curious about the inner workings.
Either way, the CSC method should most definitely be mentioned and preferably in large bold fonts. Not because you want to use it after landing, but because you might accidentally do it in flight while attempting something resembling aerobatics. Disarming by sticks is one of the first things I disable on my 250 class mini quads for that exact reason. I always arm/disarm with a switch and sticky throttle (ie can only arm and disarm with throttle at zero).