I agree, they decided to go on the train, so they have to pay. They can abandon their journey after the ride, but jumping from a running train is nonsense.
By the way, I’ve seen numerous times large number of people walking (as by foot) the full distance from one city to another. Are those the guys that abandonned their trip, and walk back home? I never followed them, nor do I know where they are coming from. (maybe from a bulldozed station, so they decides to go home by foot?)