Probably right Snoopy but a couple of points; If Ministers are "entitled" to first class travel then why buy standard class tickets? and are not first class carriages public places just as are standard class, so the argument that their matters "are not for the eyes and ears of anyone else" is somewhat disingenuous, or at least implies a belief that standard class customers (a.k.a. passengers) are somehow lesser beings than those in first.
The business about journalists just enforces my belief that many hold the attitude that they are somehow "better" than the plebs or shepple. They should be dissuaded from this as often as possible.
A cynic would suspect that it may have happened before and that they then claim back the cost of a first class ticket on their expenses (or do they have to produce proof these days?)