There's levels to safety-criticality so these aren't binary decisions. Often they are based on severity/probability/detectability measures.
For example, airbags on your car may be mandatory but automatic emergency braking not so much.
For example, airbags on your car may be mandatory but automatic emergency braking not so much.
Given that thanks to Boeing, the Lion Air crew didn’t even know the MCAS subsystem existed, and that MCAS would continue to rely on the single faulty sensor however many extra redundancies were installed, the decision not to buy seems kind of irrelevant.
This is the part I was trying to clarify. I don't know Boeing's internal processes, but there certainly could be options that are safety-critical but still optional because they are ranked low enough on the severity/probability/detectability scale.
I agree that it's wrong to blame Lion Air as the consumer. The fault seems to be in Boeing misapplying the risk categorization.