Spot on. I work on board for Cross C*ntry - equally well thought of I'm sure. USUALLY, all reservations are clearly displayed on small electronic screens above each seat. And even if these fail then the staff carry with them old fashioned paper reservations that are attached to seat backs. So, if people can't be bothered to check the availability of a seat they want, they shouldn't be surprised when nice people like me come and turf them out. That said, Megson is not somebody I like so on this occasion fair play to the OAPs.
Regular train travellers will not be surprised to learn that even if you take the time and trouble to pre book seats - usually done as a cost saving excerise - an actual seat is still not guaranteed, as stated in the Conditions Of Carriage. Any train ticket only acts as a promise that the holder will be conveyed from and to stated stations. No more.