Right, I've noticed a guy, every morning, trying to pay a small fare with a £20 note. I always hear the examiner say "I can't change that! You'll need to buy one at the station" and walks off. Thing is, is that he gets off at Yoker, which has no ticket selling facilities. He does it everyday. Clockwork and with different examiners. Is this a common scam throughout the railways? Thanks!