These problems are a lot of fun and in most cases there are interesting general lessons in their solutions, but the way the interview system seems to work is that every year there's a new book or sheet of puzzles that everyone memorizes and then pretends to have never seen before when asked during an interview.
Yeah, these puzzles are too unique and are in many cases well known problems/paradoxes that candidates are likely to know. Interviewers might be better served by asking a generic, LSAT-style logic game or a somewhat simple but time consuming math problem (maybe polynomial factorization).
