There is a slightly less ethical way to do this, you buy a ticket that mows you to travel at any time of day. Then when you have made your trip log on to realtimetrains to find a train on your route that was delayed and then claim that as your journey.
Now your ticket is sometimes scanned when you enter or leave a station but this is rare and even less likely to be scanned on the train by a conductor.
Anyway that is something that someone could do