I However, there will be thousands of people out there who have no idea which TOCs operate services between London and Birmingham, who have no idea that more than one TOC could possibly operate on the same route, or who just wonder why Network Rail/Railtrack/British Rail paint trains in different colours! For some people, a ticket saying London Midland Trains only means they can only use trains that go between London and the Midlands. And to them, that's obviously what it means..
Well they'll just have to learn about the industry structure the hard way won't they. Ignorance of a rule does not provide an excuse to break that rule.