This is neither a dispute nor a prosecution but I'm posting because it's an interesting example of how your brain can lead you astray. I have an Oyster with an annual zones 1-4 Gold Card plus top-up money for travel outside my zones. Went to Epsom to have dinner with a friend, tapped in at Waterloo and only on the train thought "damn it, Oyster doesn't go out to Epsom". Knew there were barriers at Epsom so stayed on, was willing (although hoping not to have to) pay a penalty fare and that is in fact what happened. Fair enough - have read enough to know that a PF is for honest mistakes and the RPI obviously realised this was one. BUT - when he asked me what fare I needed, I said "well, from Ewell West" - because in my head that's what I had covered on my Oyster. Of course he then pointed out that I didn't because there was no way to tap out at Epsom (barmy, but for another thread) and I realised that my brain had let me down. He was fine - presumably he could see where and what time I'd tapped in and £20 would cover both the Ewell and the Boundary Zone 4 fare I needed, but I think I'm massively clued up on fares yet got this completely wrong. Have more of an understanding of how people get themselves tied up in knots because their internal logic doesn't match the reality. That's it, really - over and done with and lesson learned.