Do you have a source for this? I can't help but think about the person in this clip: https://www.youtube.com/watch?v=LlCEmPF4-V0. You think you can learn much about her from that interaction?
I've interviewed people who didn't know the answer to some of these tech questions, and honestly, I was more impressed by them calming saying "I'm not sure on this one, I would probably need to go look it up".
Why worst? If you're not given an offer, nothing changes. You've spent somewhere between 45 minutes and a day, got some interview practice and all is basically status quo. But, if you're given an offer, you are now faced with having to weigh the pros and cons of accepting it.
I acknowledge there are some situations where you might pass the interview even without arriving at the optimal solution, but those are probably the exceptions.