I have an annual travelcard on my Oyster and only a few pennies of PAYG credit. Arriving at my home station the other day the gates were open but I still touched as out as normal… or so I thought until I checked the app and noticed a “missing touch” on the journey- thinking about it, I think a card clash may have caused the exit not to be registered properly. Happily though, I wasn’t charged for this and still seem to be able to use my Oyster normally.
Anyway, I was wondering: why wasn’t I charged for the incomplete journey? Is it because I didn’t make any further journeys that day so the system assumed I was at my home station? Or because I didn’t have enough PAYG credit to cover any penalty? Or some other reason?