There exist good interview questions, where you give lots of facts to the candidate and make it clear that they can ask if they don't remember the order of arguments to reduce(). (In fact, a good way to put them at ease is to admit that you don't remember either, and are just looking up the documentation :-P )

But if, given those bare facts, they can't write a legible and correct binary search even over multiple iterations, or reason about O() complexity of an algorithm they either just implemented, or just came up with, they are probably an STE.

In my experience, these people fall into one of two categories: new graduates who just barely scraped through their college classes, and people misrepresenting their past jobs in QA or product management as programming experience. (That isn't to say that non-CS-majors shifting into coding can't be great engineers - I know several! But when interviewing one, you can't make the assumption of basic competence, and it's a red flag if they play up their non-programming work rather than talk about actual coding experience/studies.)