I shall play devil's advocate here.
e.g. A passenger holds an Off Peak day return Inverkeithing to Edinburgh (rtn. portion) & a Fife Concession day return from Leuchars to Inverkeithing (again rtn. portion) and is on an express service from Edinburgh to Leuchars that does not call at Inverkeithing.
Prior to departure the guard makes an announcement that certain tickets are not valid on this particular train including combination tickets where the train does not call at the station where the passenger changes from one ticket to the other (seasons/rovers excepted), this specifically excludes Fife Concession tickets as the train does not call at Inverkeithing, the guard also states that any passenger not sure as to the validity of their tickets should speak to him prior to departure, & states his location.
The said passenger, holding a combination ticket where he changes from one ticket to the other at a station where the train does not stop, approaches the guard and is told that his tickets are not valid for this train, notwithstanding the fact that the man on the platform stated that this train was the next train to Leuchars, but is told, however, the time & platform of the next semi-fast service that would be valid with his ticket combination. He is also informed how much in excess fares would be required to make his ticket combination valid for the train he is currently on.
The passenger does not wish to pay any extra fare and leaves the train, he and/or his relative(s) feel that he has been thrown off the train and forced to wait for a slower service. The passenger's relative contacts customer services on their behalf to confirm the policy re combination tickets, and is given the information that the guard was correct in his implementation of the rules. This, in the passenger's and their relatives viewpoint, confirms the railway's policy of throwing pensioners of the train.
Now, there is a well known Scottish song "You cannae throw your Granny off the bus" - this could equally apply to trains in Scotland - In my view there are very, very few pensioners asked to leave trains due to ticketing issues. The worst that may happen is a TIR form but I assume the normal course of action would be - "advice given re ticket validity for future travel"
I believe that the OP's post is a misrepresentation, (I will let the forum decide is it is an understandable misrepresentation), of the system & policies in place re combination tickets. I would like to know from the OP the specific journey travelled & the specific combination of tickets held for your example given. Only then, subject to further clarification if necessary, can we comment fully on the alleged incident.
Looking forward to your reply.............