I am among the lucky ones to have only had this happen once, but when it happened to me it did turn into a bit of a scene.
returning from my summer leave as a newly promoted Leading Seaman (Leading Hand, killick, Insert Sailor joke here). I decided to pre-book my travel as some of my oppos had informed me i could save money. Whilst I was about this pre-booking malarky for the first time I thought "why not go first class" so I booked my first class ticket for the NXEC part of my journey.
Now to the meat of the story. I board my train to find a very smartly dressed Gentleman sat in my seat. Now as I was on duty when I arrived at my base I was wearing my uniform to save on time, and because I was proud of my new anchors
. I had a debate with myself weather to ask this Gentleman to move as I didn't want to cause a fuss, I elected to look for another seat. There were no remaining FC seats and I was damned if I was travelling cattle class when I had paid for First.
So I returned to my booked seat and said to the Gent " Excuse me sir, but you appear to be in my reserved seat." I expected a few grumbles but not what he said next.
"I'm not moving for you......Only OFFICERS can travel first class".
I was speechless at how outdated this man's opinion seemed to be. It felt like the whole coach was staring at me. I felt very embarrased (I was only 18). Not knowing what to do I found the train manager and explained my problem. He was very helpful and accompanied me back to my seat where the Gent spouted his "Officers only" bit again. The TM then asked to see his ticket. Only for him to produce a Standard Class ticket. The TM duly sent him packing and I settled down into my seat, and was shocked to receive applause from the rest of the coach.