“Yes, a waiter had no authority to challenge him or anyone else.”
In common with almost all train operators, Virgin provides “at seat” food and drink service only in its First Class carriages. On less busy services (a rarity these days) they will occasionally allow Standard Class ticket holders occupy a First Class seat and take a meal. I have travelled First Class on Virgin quite a bit and have seen people simply pitch up to try to take advantage of this service by simply sitting down without first asking the catering manager or waiter. They have been asked to leave when they failed to produce (for the waiter or catering manager) a First Class ticket.
The Network Rail Conditions of Carriage say “You must show and, if asked to do so by the staff of a Train Company or its agent, hand over for inspection a valid ticket and any relevant Railcard, photocard or other form of personal identification…” Nothing about it being only guards, conductors or train managers. Simply “staff”. It is quite obvious that to control the seating in a First Class carriage where meals are being served, the staff there will sometimes need to inspect tickets.
Anyway, as usual, fuss over nothing (about which we probably only have half the story at best). Mr Smith showed his ticket and life went on. Except that he had to explain the minutiae of his tedious life to his Twitter disciples.