To RPIs and other staff: when doing ticket checks on routes where buying before boarding is compulsory, approximately what percentage of passengers would you say do not have a valid ticket? From what I've witnessed on FCC it's usually about 1 person per (full) carriage, or around 1-2%, which strikes me as pretty good considering how infrequent the checks are. Of course that's generally during commuting hours. Is it worse in other parts of the country? What is considered an unusual or unacceptable level?