[lewisl9029]

> Someone who's actively working through it will pause, they'll hesitate, they'll get things wrong and have to correct themselves.

Candidates who know the solution can and sometimes will do the same. Sure, you can try to catch candidates that try to fake it, but then the process becomes a cat and mouse game between the interviewer and candidate that distracts both parties from the real purpose of the interview, which is to find the most qualified candidate for a position.

None of this would be necessary if the interviewer simply used a lesser known question (or better yet, a more practical question adapted from something taken from the part of the codebase that they'd be working on) to begin with.