This happened on terra firma but I think is still applicable: was working front desk in a hotel where a large group of people from a travelling art exhibition were staying. They gallery where the paintings were being shown was just next door. Thinking it might be worthwhile getting the artist's autogragh on one of the brochures I asked the tour manager if I could get her signature as "I am a big fan of her and her work." He just looked at me and said "She died 7 years ago."
Ok...not that big a fan...how embarrassment!
