I would just ask, irrespective of whether the train has to stop at of before the point where the passenger stops using the season ticket and starts using the off-peak ticket, isn't this another drawback of PAYG compared to tickets?
PAYG just seems to be a massive impediment to split ticketing. In the past I've worked out the cheapest way to get to Gatwick for a lunchtime flight was to tap in at my local station, tap out en route as soon as the peak restrictions had ended, then tap back in again to pay the off-peak fare for the rest of the journey (although the split would be cheaper than the through fare anyway). In the end I did the same split but with paper tickets so that I didn't have to get off and step back a train.
And now as Mike's question illustrates, even where a season or daily zonal ticket is held and an extension fare needs to be paid, the only ways to get an off-peak fare for the extension where the relevant portion of the journey is off-peak, is either
- using a stopping train and getting off to tap out and then in again or;
- using a paper extension ticket (I don't think they're available as e-tickets, though not really clear why on earth not).
Because oyster is just going to take the tap-in time at the start of the journey and if it was during peak hours, it will charge the extension fare at peak rates.
If the rail industry still considers that paper tickets should be phased out, I would suggest it ought to be doing the necessary work to make sure the alternatives don't penalise passengers. Maybe in a case like this it would be possible to get the Putney-to-wherever ticket as an e-ticket or add it to a smartcard, but I would argue Boundary Zone tickets also need to be fulfillable by e-ticket or smartcard.