I love hearing about research like this. But yeah, that would be an ethical dilemma. Especially determining how much you trust that your system works, and proving that they are of sound enough mind to make such a decision even if they’re answering yes/no.
I don’t remember the article raising questions about determining the patient’s mental sanity as to whether an affirmative answer to “asking to die” was enough. That’s an aspect I never even considered.
I also appreciate that the researcher, who is clearly very smart to even have gotten this far in understanding the technology and its implications, is also smart enough to understand they themselves don’t have the full capacity raise and answer this question ethically to be able to move forward.