I think someone should stop saying something without valid proof and / or personal experience. We probabaly have enough of those in CX / HK forum. Different Views are always welcomed but not pure speculation.

Regarding the bumpy aicraft I think Boeing has some sort of warranty / maintainece plan attached to it. As airline business you always have to plan ahead for additional plane to replace faulty ones which need AOG (Aircraft on Ground) maintainece or (A-D) checks. When it is at outport it's always another story.

From this it teach me to buy travel insurance everytime. It become handy when it comes to tech issues