MIG wrote:

When I've started or finished PAYG DLR journeys at Stratford, I've
only ever touched at the barrier with the outside world (by the NR
ticket window) and had no problems, although presumably if I'd touched
the readers on the platform as well (the old platform by the Central
and NR) it would have made no difference unless I hung around having a
cup of tea etc and I'd have two unresolved journeys.

I think a large part of the problem comes if you enter the station from one
of the lines. For example does someone changing between the Central and DLR
need to touch the readers on both platforms? What about someone who has to
come through the Jubilee barriers onto one of the other Oyster lines? What
about someone coming off the mainline from further east and starting to use
Oyster for the rest of their journey?