Not unimaginable at all. In a world where surgery was run like software "engineering" [1], we would interview surgeons this way.
Why don't we interview surgeons this way?
(a) Because surgical training is via apprenticeship. For any given surgeon, you can ask "which group of other surgeons taught you everything you know? Which ones signed sworn statements that you are minimally competent?" Then you can find those senior surgeons and ask them candid questions about the candidate. This is always possible. If a surgeon turns up without such references they don't get as far as an interview. ("I taught myself surgery from blog posts, and I practiced on my cats?" Eeeek. NO HIRE.)
(b) Thanks to the long history of medicine and its very serious life-and-death implications, surgery is a very thoroughly attested event with a very definite chain of responsibility. Look at a hospital's records for a given surgery, and you will get a complete list of everyone in the room. If the surgeon was the only surgeon in the room, you can be fairly confident that they handled the operation themselves. And though I'm not sure there's an actual law that forbids a surgeon from handing the scalpel to a nurse, or an intern, and having them do everything, that would (a) not be something they could do in secret; everyone in the room would know and (b) the surgeon-of-record would still be the responsible party: If something went wrong in surgery guess who would be sued?
What I'm saying is: It is hard to bluff being a surgeon. Which is not to say it doesn't happen: For various all-too-human reasons, doctors and nurses do cover for each other, and scandals occur. But it's not like software, where the level of bluff is really, really large. Software "engineers" are often self-taught by necessity, especially in the tasks they actually do all day; their work has no legally defined standards or practices; there are so many ways to solve a given problem that two engineers with the same job title and official responsibility may have completely different skillsets; they work largely inside their own heads where nobody can see what is going on; they can very easily copy others' work, or sit in the corner while the rest of the team does the heavy lifting and then claim full credit.
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[1] For this post, I'm going to use these scare quotes to distinguish "software engineers" like myself from actual Professional Engineers, who are like surgeons and are not, in fact, asked to build little bridges out of Lego bricks during their job interviews.