To me engineering is all about the skill to approach solving problems and how you go about that. Good engineers newer get stuck, unless it’s a very uncommon problem they are trying to solve. Like you say, there is a space to to test whether they can code themself out of a loop, but you really want to see how they would work if they work for you - that is the point of the interview. So make sure you design your tests accordingly - this guy makes the argument and I cannot agree more https://youtu.be/bx3--22D4E4