I agree with both you and the parent to some degree. I have experienced interviews that went badly because they were in an IDE I wasn't familiar with, or in Leetcode (never used it). So I'm distracted by how to use the tool rather than how to code the solution. But I can also see how stuff like finding a substring is easy - most languages have a function for it. But at that point, you're testing different things - problem-solving vs rote memorization of a provided function.

I feel like a good middle is to allow Google for documentation searches, not solution searches. Without searching (or IDE with radix completion), I'd probably fail the test for not knowing the syntax off the top of my head.