Some operators use door nets rather than straps, not only in the hangar. Good idea if you ask me.
At my operator we have the 'no door to be left open w/o steps/truck' rule but it is frequently ignored (and duly reported) A lot comes down to the training and 'care factor' of the ground staff on duty.
I have also heard of a 'paper procedure' at certain operators whereby steps cannot be removed without a signed slip from the cabin crew onboard. I would guess these are the operators that have suffered similar accidents and have learnt from the experience.
SOP is there for a reason, especially when you're dead tired after an ultra-long-haul flight and following them is the only thing between you and a hard landing on the pavement! Being trained properly at my first airline to always hold the handle definitely saved me at a second- wind took the door as we were closing up and I am certain I'd have gone out had I not been following the SOP. Colleagues now laugh at me because I always hold on whenever near the door but you'd be crazy not to at the heights we're talking... imagine going up a 3 story building, standing on the parapet and not holding onto something- just asking for a problem.
(Note, I am in no way saying this is what the poor pilot did/did not do, just adding to the discussion on door SOP)