There are two different questions here....
1) Did the crew in this particular case make the correct decision according to current regulations and policies?
2) What should the regulations and policies be?
Stagger, are you actually reading this thread?
The crew did not contravene the regulations of the FAA or the CAA! Can you read English? They did exactly as 4 engine long haul crews, American, British, Australian and worldwide have been doing for years.
Where on Earth has question 2 come from now? We are not discussing what the regulations
should be, for goodness sake, shall we stick to the question in hand- it appears hard enough for some of you to understand that let alone going hypothetical! You are some sort of scientist who has chosen to apply his non-aviation scientific principles to a subject you know nothing about, other than the feeling that the little you do actually know offends your sensibilities. It would be far better if this discussion was limited to those that know something about aviation and balancing risks, because quite frankly, some of you do not know what you are talking about. The glib 'they should have landed back at LAX' ignores a lot of additional dangers and risks they didn't need. Landing en-route would not have solved any problems and created more. They did the right thing, exactly as I would have done and almost all 4 engine long range pilots would have. You are achieving nothing with your daft theories of failure probabilities. Why don't you just give it a rest?