Not at all - if the pilots have not been trained or briefed properly - or if they have been put in a position where safety is compromised and have been coerced into flying anyway, then at least some of the responsibility lies with the airline
If you are a person who considers himself a responsible professional and intellectually honest .. you never accept or do what you explain above
However, if you agree ... you do not need excuses or loopholes and must agree to be designated as responsible if anything happens because of you
In my professional life I have been sometime (exceptional) forced to do things contrary to or not in keeping with the rules .. and always by verbal way (as always happens)
I always said I wanted it to be postponed by a written order signed by a senior or responsible person ...
It has always been told that they were going to study another way to do the job and so what they had asked was canceled ...
I've never had to suffer because of this trouble