Jonathan Harris wrote

The problem comes from needing to know exactly where the OSIs are,
how
long you are allowed, which interchange validators you need to touch,
not knowing how to cancel an OSI and knowing the journey durations.
You've almost got to check the single fare finder before travelling
which might be practical for someone with a phone wth the internet but
not the normal passenger.

What you call "how to cancel an OSI" previous discussions have referred
to as "how to force journey termination".

As noted, touching on a bus does this as does re-entering the system at
the same gateline.

There is no evidence that interchange validators make any difference
even to the allowed journey time- I don't see what help the single fare
finder is with OSI either.



and out. Presumably the TfL benevalence with refunds for this kind
of
thing won't last forever.

Since they have a (ex post facto) refund system in place it /could/
last forever.

"Our aim is to ensure that Oyster always charges the lowest fare. When
it doesn't we will refund the difference".

Perhaps TfL could run a competition in the Brainteaser section of The
Times for a solution that matches the Oyster PAYG constraints ?

A "Finished with current journey" /blue with pink spots/ validator
outside every gateline at every OSI would do it.

--
Mike D