To be very honest I think that this one is a case of "there by the grace of god go we".Having watched the video a least 20 times to see what caused the event, the only thing I can see resulted in this accident was that the end of the trench gave way at a critical moment,if you watch the time line it all happens in less than 7 seconds,a very short time to turn a 20t+ excavator on it side.
If we were to be really honest with ourselves we all have tracked back with our booms & sticks in this position with no adverse effects,the superstructure was in the right position for what he was doing, tracking back when personel were around, so he chould see his direction of travel.
If I was in the operators boots I would be glad of the video as it shows that circumstances beyond his control resulted in this mishap ,one for the 5% I think,the only thing I would be concerned about was the man in the trench under the machine.In my humble opinion its in Belgium/Holland and what looks like a leibherr.
There are a lot of reckless operator/drivers out there and I wouldn't class this one in that bracket.
Stock:my2c