We are getting confused here between this concept of 'legislation' and manufacturers' responsibilities - and commonsense. I know EXACTLY what Centaurus is saying, and I assume that 'legislation' is not what was meant, but the issue is:
Can things be improved - yes
Should they be - yes
Why should anyone disagree? 'permFO' has it in one. Would 100+ be alive if the Helios a/c had a clear, obvious and unambiguous pressurisation warning that crews were trained on and aware of? Leaving aside the other 'mysteries' of that accident, I know the answer is 'possibly' but we must not ignore the options.