There are some who are of the opinion that the byelaw is satisfied by presenting a card that *could* have been used to start the journey, but I think that is being too narrowly focused on the letter of section 18.2 in isolation rather than considering Byelaw 18 as a whole: you have to have a valid ticket when you board and you have to hand over *that ticket* when requested, unless there was no way to pay for a ticket or you were given permission to board without one.If so, you're automatically guilty under byelaw 18 (2) because you failed to show your ticket (if the byelaw means you have to show a valid ticket)