Well I can't speak for other interviewers especially at other organizations, but I try very hard to make it a positive experience. In fact I'll give as much help as necessary to get to a working solution, within reason. I would much rather fix the lambda syntax myself or help the candidate find an example on stackoverflow so we can go back to the interesting part. If the interview ends with a working solution but needed a ton of help, the candidate probably did not pass but maybe they learned something. And maybe they'll tell their peers that it seemed like a place where they could fail without embarrassment, collaborate, and learn.