To be fair, maybe not THAT common on FCC as I am not sure it does any ticket promotions via its own website?
Still no excuse for the way the RPI ignored an explanation and didn't want to check, but perhaps a reason to explain why there was the misunderstanding?
Some RPIs simply need to eat humble pie and admit when they're wrong. Everyone can and will make mistakes, but I rarely have a problem with someone making a mistake - it's how that person (or a company) deals with things after that matters.
Like a RPI that gave out a PF to someone in first class on a train that, when he reached me, I was able to point out was declassified. Not only did I get an apology, but the RPI quickly went back to cancel the PF he'd just issued and apologised to him too.
I can well imagine some FCC RPIs would have been worried about being seen to have made a mistake and would make things worse by insisting on giving me a PF too and insisting I was wrong to save face.