My argument is that if safety and liability make the use of AI without fully understanding the implementation impossible, the model is arguably not good enough.
No such process exists for a model to take a design seriously that can kill people.
When we manually tested nuclear power plant controlling software, each test case was printed out on paper and tested and then signed by the tester. A lot of paper was produced and archived for each software release. (Archived for as long as the software was running in any nuclear power plant).
Everyone understood, that in a case of significant accident at the nuclear power plant, accident analysis would be done and if the root cause was an software error, this could have possible legal consequences for the developers and testers. (Of course nuclear power plants have many independent and redundant hardware controlling mechanisms, but incorrectly working controlling software could damage the power plant in a very costly way).
I imagine that the requirement is that after testing, you are confident that the product is safe.
I think you're entirely wrong, and we can leave it at that, seeing that you're clearly unwilling to engage constructively.
If you can't leverage AI to build a safe and useful robot without fully understanding the implementation, the model is not good enough.