Just read the >500 m thread and didn't want to threadjack...

[FoxhallGH]

Foxhall: What "altitude hold" function"? News to me but that's no surprise.

Sorry, my Bad - looking closer - it's an 'Intelligent Flight Mode' and I've called it 'Altitude Hold' where it's actually labelled as 'Terrain Follow'.
DJI GO 4 Manual: The Pilot's Handbook - Page 9 of 10 - DJI Guides

 

[FoxhallGH]

I would say as the law is all about your intention, and the height AGL is about not colliding with other air traffic, in this video, would any light aircraft, helicopters, microlights, gliders be that close to the cliff face? I expect not, so as far as risk assessment goes, he could see vlos, he could also definitely see any other air vehicles coming close to the cliff face, at that location I expect there to be not a lot of background noise except wind, so he could hear anything coming he couldnt see that was under motor power.

For the drone laws, they are open to interpretation as any laws are, any court would ask " did he intend to cause harm, and did he take necessary steps to ensure he was flying safely. In my opinion he could answer no to the former and yes to the latter.

Quite correct @Spike151 - although we are talking about two entirely different things here ... Although you may have the right to go over the lip of the Mesa and descend while adhering to local rules & reg's regarding clearance from terrain ... That doesn't absolve you from having to ensure that the skies are clear - which is where (as you rightly point out) the requirement to keep visual line of sight comes in.