Comment by oytis

I kind of see the issue, but it would be a problem with any live interviewing, not just live coding. You can equally forget all the anecdotes you prepared for behavioural questions, and surely may not be able to come up with an answer to a question you are not prepared for (happens to me more often than not being able to traverse a binary tree to be honest).

Not sure what the answer should be apart from hiring people you know - personally or because they have a personal brand.