I strongly disagree. This is nothing. You can sort out if someone is using something like this to cheat. You have a conversation. You can ask conceptual questions about algorithms and time complexity and figure out their level and see how their sophistication matches their solution on the LeetCode problem or whatever. Now, if you have really bad intuition or understanding of human behavior then yeah it would probably be hard but in that case being a good interviewer is probably hopeless anyway.