P2 V+ Newbie here - so forgive me if this seems a dumb question regards P3!
You apparently cannot turn-off the vision positioning system on P3 - so if you fly low across a field (less than 6ft? where the VP may be monitoring) which then drops away (cliff edge) rapidly - (thinking of Beachy Head in UK) - will the Phantom, when it goes over cliff edge, suddenly drop out the sky trying to re-engage a 6ft above ground flight level??

You can fly "down" below the original take off altitude.

Since the Phantom also has a barometer I guess it wouldn't. But DJI has to answer that.