This doesn't much sense to me... you get off your weight belt before the BCD
It's a nice safety notion, but it means you have to take your belt off while wearing tanks on your back. Very easy in the water, OK sitting down, and really uncomfortable to do standing up on a rocking boat.
For me the doff order has always been either:
Belt+fins - pass up - climb aboard - BC+tanks - mask, or
Fins - climb aboard - BC+tank - belt - mask.
Even in light of this accident, I still don't plan to wear tanks on deck any longer than necessary. The high probability, low impact risk of dropping or falling with the tanks outweighs it. Perhaps just be more sure not to delay the procedure and get the belt off right away. Somewhere like Phi Phi, I'd only have a couple pounds plus tools on it, so it's easy to forget it's there.
More focus should be on novices like DSD and students. First, stop overweighting them. Second, ensure that belt removal should be second nature before one puts it on at sea. And third, supervise their don and doff procedure, so this doesn't happen. Even if you teach them to do the belt last/first, they won't follow it without supervision, the equipment is too unfamiliar to them.