On Dec 13, 9:07*pm, Mizter T wrote:

[much cut]

Yes it will. I'll stop pussyfooting around so much and expand on this.
I don't know the official terminology but touching on interchange
validators is in effect treated as a 'soft exit' from the PAYG system
- in other words it means that the passenger might be doing one of two
things, either
(a) finishing their PAYG journey and presumably continuing using
another paper ticket, or
(b) touching-in midway through their journey at the point of
interchange, and they will touch out later when they exit the system
at their destination.

In other words it is ambiguous, because the system cannot know what a
passenger intends to do. In any case if a passenger is inspected later
then their Oyster card will be legitimately validated (within the time
limit at least).

I'm not going to spell it out, but you can see how this could be
abused by someone who wanted to sidestep paying the whole fare due.



And for that matter do the Jubilee barriers work to both interchange Canning
Town to Leyton and finish the Oyster section of Canning Town to non-Oyster,
or does the latter require touching out on the platform barriers as well?

Again the unusual Jubilee line gates have the exact same 'interchange'
attributes as the interchange validators, because a passenger might
fall into either scenario (a) or scenario (b) which I outlined above.



Many (inc. Paul C) have said that better information should be
provided - I suspect the basic problem with providing this information
is that it might assist people in working out the potential loopholes
that are inherent with interchange validators, something I've hinted
at in the past though I note one contributor to this ng recently laid
it out in a straightforward manner. In other words spelling out
exactly how they work will assist people to abuse the system.

So instead it encourages people to get confused and make mistakes because
they don't know and can't find out how to do it correctly?

I suppose the point is that they can't make a mistake even if they are
'Oyster touch-happy' - i.e. the system is tolerant of people touching-
in several times. My hypothesis is that the way the system works is
not explained for fear that people will figure out how to scam it. As
more ungated National Rail stations enter the fray as more routes
accept PAYG, this issue only increases.

Not that I plan to try, but does that mean that if I was to get on the
DLR at, say, Greenwich and touch the pad there to start the journey,
and then keep jumping out and touching at various stations along the
way and then eventually exit through the barriers at Bank, would I be
charged for just the one journey or have a string or unresolved
journeys?

But I am not clear on whether there is a distinction between
"interchange" validators and other standalone validators (ie all along
the DLR) which are neither entry nor exit.

Maybe if I restricted my touches to Greenwich, Heron Quays and Canary
Wharf and then ended the journey at Bank it would be different from
touching at Mudchute etc.