After reading several posts where honest mistakes have been made by passengers getting on a wrong train and not knowing or realising the stopping patterns, ending up one or more stations along the line, than they intended. I know London Midland stopping patterns fairly well, so I don't have a problem. I know someone who made a mistake wanting to go to Apsley but next stop was Hemel Hempstead, they just caught the next train back. For me, using Thameslink from St Pancras northwards with a Zone 1 to 6travelcard. I have to be really careful the train actually stops at West Hampstead and not non stop to St Albans, the platform indicators aren't that clear on the platform. Should someone travel further than they intend because they've genuinely boarded a train by mistake that doesn't stop at the station they wish to alight, there's 2 options IMO 1)Be honest with gate line staff and buy a return ticket. (Assuming there's no RPI to dish out a Penalty fare) 2)Take a risk and just travel back to intended stop without a ticket and hope there's no, on train ticket inspections.