@nedbat consider the problem of a structural engineer testifying at inquest over a bridge failure. The choice to defer decisions to an unexaminable generative model is qualitatively different to decisions deferred to one that is fully explainable where all the inputs can be forensically examined.

I think there is a good argument that this is the line which marks the project as a "serious engineering endeavour" from a common understanding of what it means to be an engineer because it gets to the ethical component of the profession. If the methods are obscure to forensic audit then you may be an engineer but you're obviously not being serious - it's a repudiation risk.

The engineer must take authorship of code produced by tools and incurs the risk of misrepresenting authorship of poor quality code produced which could be little more than lossy-compressed copies of stolen copyrighted training data with error correction informed by custom prompts.

Can you work through these issues to your own satisfaction for a project according to a known risk profile? Sure. Can you pass it off as best practice? I don't think so. It's a matter of engineering ethics which determines whether it gets to the point where a coroner decides the answer to that question.